Pub Date : 2026-03-10DOI: 10.1016/j.mtphys.2026.102068
Xiangning Quan, Junwei Zhang, Yiqun Zhao, Chaoshuai Guan, Lili Zhang, Hong Zhang, Zhe Wang, Jun Wang, Mingsu Si, Yong Peng
Electric and magnetic fields are essential for the precise description of physical phenomena in nature. Accurately visualizing their distribution within materials is critical for understanding fundamental properties and enabling advanced applications. However, traditional techniques for characterizing electric and magnetic fields in materials frequently suffer from poor sensitivity and resolution. In contrast, differential phase contrast scanning transmission electron microscopy (DPC-STEM) has proved to be a highly effective and robust technique for mapping these fields, offering both exceptional sensitivity and high spatial resolution, even down to the atomic level. This review systematically outlines the fundamental principles and recent progress in DPC-STEM, highlighting its unique capability for direct electric and magnetic field visualization. We further compare DPC-STEM with four-dimensional scanning transmission electron microscopy (4D-STEM) and discuss practical aspects of its experimental implementation. Finally, we conclude by addressing current challenges and future prospects in this rapidly advancing field.
{"title":"Visualizing electric and magnetic fields in materials: Principles and frontiers of differential phase contrast scanning transmission electron microscopy","authors":"Xiangning Quan, Junwei Zhang, Yiqun Zhao, Chaoshuai Guan, Lili Zhang, Hong Zhang, Zhe Wang, Jun Wang, Mingsu Si, Yong Peng","doi":"10.1016/j.mtphys.2026.102068","DOIUrl":"https://doi.org/10.1016/j.mtphys.2026.102068","url":null,"abstract":"Electric and magnetic fields are essential for the precise description of physical phenomena in nature. Accurately visualizing their distribution within materials is critical for understanding fundamental properties and enabling advanced applications. However, traditional techniques for characterizing electric and magnetic fields in materials frequently suffer from poor sensitivity and resolution. In contrast, differential phase contrast scanning transmission electron microscopy (DPC-STEM) has proved to be a highly effective and robust technique for mapping these fields, offering both exceptional sensitivity and high spatial resolution, even down to the atomic level. This review systematically outlines the fundamental principles and recent progress in DPC-STEM, highlighting its unique capability for direct electric and magnetic field visualization. We further compare DPC-STEM with four-dimensional scanning transmission electron microscopy (4D-STEM) and discuss practical aspects of its experimental implementation. Finally, we conclude by addressing current challenges and future prospects in this rapidly advancing field.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"32 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147392479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-20DOI: 10.1016/j.mtphys.2026.102056
Zhipeng Li , Xudong Li , Hongyan Zhang , Jie Ai , Haiyang Zhang , Chu Chen , Ling Zhang
A high-performance ammonia (NH3) gas sensor based on ZnO/Ti3C2Tx composites was fabricated using the hydrothermal method. The gas sensitivity test results show that the composite of Ti3C2Tx and ZnO improves the sensing performance of Ti3C2Tx-based NH3 sensor at room temperature. The response of ZnO/Ti3C2Tx to 200 ppm NH3 is 158.7 and the response/recovery time is 3.6 s/0.9 s. Additionally, the sensor demonstrated excellent humidity resistance and long-term stability. This improvement is attributed to the introduction of additional free oxygen species and oxygen vacancies on the Ti3C2Tx surface by ZnO, exposing more active metallic Ti sites. Simultaneously, reducing the number of -OH groups increases the number of -F groups and enhances the polarity of the -OH groups. DFT studies indicate that higher surface oxygen vacancy density promotes the formation of highly active and unsaturated Ti sites, thereby enhancing strong chemical adsorption of NH3. Concurrently, the reduction in -OH groups increases the polarity of -OH, thereby improving the adsorption efficiency of NH3 molecules. Thus, modulating the Ti3C2Tx surface with metal oxides to reduce hydroxyl groups and increase oxygen vacancies promotes the formation of Ti metal sites, offering a novel approach for developing high-performance room-temperature NH3 gas sensors based on Ti3C2Tx.
{"title":"Interface design of ZnO/Ti3C2Tx composite and study on its ammonia performance at room temperature","authors":"Zhipeng Li , Xudong Li , Hongyan Zhang , Jie Ai , Haiyang Zhang , Chu Chen , Ling Zhang","doi":"10.1016/j.mtphys.2026.102056","DOIUrl":"10.1016/j.mtphys.2026.102056","url":null,"abstract":"<div><div>A high-performance ammonia (NH<sub>3</sub>) gas sensor based on ZnO/Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> composites was fabricated using the hydrothermal method. The gas sensitivity test results show that the composite of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> and ZnO improves the sensing performance of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>-based NH<sub>3</sub> sensor at room temperature. The response of ZnO/Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> to 200 ppm NH<sub>3</sub> is 158.7 and the response/recovery time is 3.6 s/0.9 s. Additionally, the sensor demonstrated excellent humidity resistance and long-term stability. This improvement is attributed to the introduction of additional free oxygen species and oxygen vacancies on the Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> surface by ZnO, exposing more active metallic Ti sites. Simultaneously, reducing the number of -OH groups increases the number of -F groups and enhances the polarity of the -OH groups. DFT studies indicate that higher surface oxygen vacancy density promotes the formation of highly active and unsaturated Ti sites, thereby enhancing strong chemical adsorption of NH<sub>3</sub>. Concurrently, the reduction in -OH groups increases the polarity of -OH, thereby improving the adsorption efficiency of NH<sub>3</sub> molecules. Thus, modulating the Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> surface with metal oxides to reduce hydroxyl groups and increase oxygen vacancies promotes the formation of Ti metal sites, offering a novel approach for developing high-performance room-temperature NH<sub>3</sub> gas sensors based on Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub>.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102056"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146778091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-03-07DOI: 10.1016/j.mtphys.2026.102065
Yixin Ding , Yue Kuai , Heng Liu , Caiyang Wang , Yingtian Xu , He Zhang , Yunping Lan
Two-dimensional (2D) π-conjugated coordination polymers (CCP) are of significant interest in various fields because of their excellent electrical conductivity, abundant active sites and porous structures. Nevertheless, their applications for ultrafast photonics and nonlinear optics still need to be further explored. The preparation of atomic-scale high-quality ultrathin CCP nanostructures remains a great challenge. Moreover, 2D van der Waals heterostructures (vdWhs) have attracted considerable attention owing to their unique photoelectric characteristics. Based on this, herein, two types of ultrathin CCP nanosheets of CuHHBNs and Cu3(BHT)Ns (HHB = 1,2,3,4,5,6-hexahydroxy benzene, BHT = hexahydrophobic benzene) with the thickness of 4-6 nm are prepared via surfactant-assisted synthesis strategy. Then, the desirable π-π stacked ultrathin Cu3(BHT)Ns/graphene and Cu-HHBNs/graphene organic-inorganic vdWhs (Cu3(BHT)G-VHS and CuHHBG-VHS) are synthesized by ultrasonic-assisted method. Based on characterization analyses and theoretical simulations, because of the π-π stacking interactions between graphene and CCP, these ultrathin vdWhs display noticeable electron cloud extension, interfacial charge transfer and improved nonlinear optical (NLO) property. Ultimately, CuHHBG-VHS and Cu3(BHT)G-VHS saturable absorbers reveal remarkable performance in ultrafast fiber laser. CuHHBG-VHS attains femtosecond fundamental mode-locking (FML) pulses and 14-order harmonic mode-locking (HML). Cu3(BHT)G-VHS attains FML with pulse duration as short as 567 fs, and 48-order stabilized HML with GHz repetition frequency. The preferable performance of Cu3(BHT)G-VHS is due to the larger π-conjugated system within Cu3(BHT) structure, which may lead to stronger electron cloud extension and more charge transfer. This work offers new pathways toward CCP-based high-performance optoelectronic systems and ultrafast photonic applications.
{"title":"Interfacial engineering of ultrathin π-π stacked conjugated coordination polymer/graphene heterostructures for nonlinear optics and ultrafast photonics","authors":"Yixin Ding , Yue Kuai , Heng Liu , Caiyang Wang , Yingtian Xu , He Zhang , Yunping Lan","doi":"10.1016/j.mtphys.2026.102065","DOIUrl":"10.1016/j.mtphys.2026.102065","url":null,"abstract":"<div><div>Two-dimensional (2D) π-conjugated coordination polymers (CCP) are of significant interest in various fields because of their excellent electrical conductivity, abundant active sites and porous structures. Nevertheless, their applications for ultrafast photonics and nonlinear optics still need to be further explored. The preparation of atomic-scale high-quality ultrathin CCP nanostructures remains a great challenge. Moreover, 2D van der Waals heterostructures (vdWhs) have attracted considerable attention owing to their unique photoelectric characteristics. Based on this, herein, two types of ultrathin CCP nanosheets of CuHHBNs and Cu<sub>3</sub>(BHT)Ns (HHB = 1,2,3,4,5,6-hexahydroxy benzene, BHT = hexahydrophobic benzene) with the thickness of 4-6 nm are prepared via surfactant-assisted synthesis strategy. Then, the desirable π-π stacked ultrathin Cu<sub>3</sub>(BHT)Ns/graphene and Cu-HHBNs/graphene organic-inorganic vdWhs (Cu<sub>3</sub>(BHT)G-VHS and CuHHBG-VHS) are synthesized by ultrasonic-assisted method. Based on characterization analyses and theoretical simulations, because of the π-π stacking interactions between graphene and CCP, these ultrathin vdWhs display noticeable electron cloud extension, interfacial charge transfer and improved nonlinear optical (NLO) property. Ultimately, CuHHBG-VHS and Cu<sub>3</sub>(BHT)G-VHS saturable absorbers reveal remarkable performance in ultrafast fiber laser. CuHHBG-VHS attains femtosecond fundamental mode-locking (FML) pulses and 14-order harmonic mode-locking (HML). Cu<sub>3</sub>(BHT)G-VHS attains FML with pulse duration as short as 567 fs, and 48-order stabilized HML with GHz repetition frequency. The preferable performance of Cu<sub>3</sub>(BHT)G-VHS is due to the larger π-conjugated system within Cu<sub>3</sub>(BHT) structure, which may lead to stronger electron cloud extension and more charge transfer. This work offers new pathways toward CCP-based high-performance optoelectronic systems and ultrafast photonic applications.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102065"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147392480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mixed-alkali engineering offers a powerful strategy for enhancing the electrochemical performance of polyanionic cathodes in Na- and K-ion batteries. Here, we deliver a comprehensive multiscale computational investigation of Na3V2(PO4)2F3 and its ion-exchanged mixed-alkali analogue Na1.5K1.5V2(PO4)2F3, revealing fundamental structure–property relationships that govern their electrochemical performance. The most stable phase configuration of Na1.5K1.5V2(PO4)2F3 emerges as the thermodynamic ground state, stabilizing an expanded yet mechanically robust NASICON-like VO4/F2–PO4 lattice. K+ incorporation markedly narrows the band gap, enhancing electronic transport, while climbing-image nudged elastic band (CI-NEB) calculations show ultralow in-plane migration barriers of 0.211 eV (Na+) and 0.243 eV (K+), enabling diffusion coefficients near 10−7 cm2 s−1. Thermodynamic analysis uncovers a sequence of stable intermediate phases governing selective and dual-ion de-intercalation, giving rise to distinct voltage plateaus with average operating voltages of 3.22 V (Na+), 3.68 V (K+), and 4.17 V (Na+/K+). Notably, simultaneous Na+/K+ extraction leads to the achievement of a high theoretical capacity of 182 mAh g−1 and an energy density of 759 Wh kg−1 while maintaining small structural expansion. ab initio molecular dynamics (AIMD) simulations confirm exceptional thermal resilience across all charged states. These insights position ion-exchanged Na1.5K1.5V2(PO4)2F3 as a highly stable, high-voltage, and fast-ion-conducting mixed-alkali platform, advancing the design of next-generation Na-ion, K-ion, and hybrid Na/K-ion battery cathodes.
混合碱工程为提高钠离子和钾离子电池中多阴离子阴极的电化学性能提供了强有力的策略。在这里，我们对Na3V2(PO4)2F3及其离子交换混合碱类似物Na1.5K1.5V2(PO4)2F3进行了全面的多尺度计算研究，揭示了控制其电化学性能的基本结构-性能关系。Na1.5K1.5V2(PO4)2F3最稳定的相构型出现在热力学基态，稳定了类似nasicon的扩展而机械坚固的VO4/ F2-PO4晶格。K+的加入明显缩小了带隙，增强了电子输移，而爬升图像推动弹性带（CI-NEB）计算显示，平面内迁移势垒为0.211 eV （Na+）和0.243 eV (K+)，使扩散系数接近10-7 cm2 s-1。热力学分析揭示了一系列稳定的中间相控制选择性和双离子脱插，产生不同的电压平台，平均工作电压为3.22 V (Na+), 3.68 V （K+）和4.17 V （Na+/K+）。值得注意的是，同时提取Na+/K+可以获得182 mAh g-1的高理论容量和759 Wh kg-1的能量密度，同时保持较小的结构膨胀。从头算分子动力学（AIMD）模拟证实了在所有带电状态下的优异热弹性。这些发现将离子交换的Na1.5K1.5V2(PO4)2F3定位为一种高稳定、高电压、快速离子传导的混合碱平台，推动了下一代Na离子、k离子和混合Na/ k离子电池阴极的设计。
{"title":"Mixed-alkali ion-exchange engineering enables fast-ion transport in Na1.5K1.5V2(PO4)2F3 fluorophosphate as a high-voltage cathode material for Na/K-ion batteries","authors":"Abdelghani Bensassi , Abdelfattah Mahmoud , Abdallah El Kenz , Abdelilah Benyoussef , Omar Mounkachi","doi":"10.1016/j.mtphys.2026.102059","DOIUrl":"10.1016/j.mtphys.2026.102059","url":null,"abstract":"<div><div>Mixed-alkali engineering offers a powerful strategy for enhancing the electrochemical performance of polyanionic cathodes in Na- and K-ion batteries. Here, we deliver a comprehensive multiscale computational investigation of Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3</sub> and its ion-exchanged mixed-alkali analogue Na<sub>1.5</sub>K<sub>1.5</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3</sub>, revealing fundamental structure–property relationships that govern their electrochemical performance. The most stable phase configuration of Na<sub>1.5</sub>K<sub>1.5</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3</sub> emerges as the thermodynamic ground state, stabilizing an expanded yet mechanically robust NASICON-like VO<sub>4</sub>/F<sub>2</sub>–PO<sub>4</sub> lattice. K<sup>+</sup> incorporation markedly narrows the band gap, enhancing electronic transport, while climbing-image nudged elastic band (CI-NEB) calculations show ultralow in-plane migration barriers of 0.211 eV (Na<sup>+</sup>) and 0.243 eV (K<sup>+</sup>), enabling diffusion coefficients near 10<sup>−7</sup> cm<sup>2</sup> s<sup>−1</sup>. Thermodynamic analysis uncovers a sequence of stable intermediate phases governing selective and dual-ion de-intercalation, giving rise to distinct voltage plateaus with average operating voltages of 3.22 V (Na<sup>+</sup>), 3.68 V (K<sup>+</sup>), and 4.17 V (Na<sup>+</sup>/K<sup>+</sup>). Notably, simultaneous Na<sup>+</sup>/K<sup>+</sup> extraction leads to the achievement of a high theoretical capacity of 182 mAh g<sup>−1</sup> and an energy density of 759 Wh kg<sup>−1</sup> while maintaining small structural expansion. ab initio molecular dynamics (AIMD) simulations confirm exceptional thermal resilience across all charged states. These insights position ion-exchanged Na<sub>1.5</sub>K<sub>1.5</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3</sub> as a highly stable, high-voltage, and fast-ion-conducting mixed-alkali platform, advancing the design of next-generation Na-ion, K-ion, and hybrid Na/K-ion battery cathodes.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102059"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147278284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-05DOI: 10.1016/j.mtphys.2026.102046
Shiqi Liu , Yingmei Zhu , Xiaobing Chen , Sheng Bi , Jie Yang , Tiejun Zhou , Bo Liu
Altermagnets, a newly discovered class of collinear antiferromagnets with vanishing net magnetization yet sizable momentum-dependent spin splitting, provide a unique platform for high-performance spintronic devices. Among known altermagnets, CrSb stands out with a large ∼1 eV spin splitting near the Fermi level and a high Néel temperature above 700 K, making it particularly promising for applications in antiferromagnetic magnetic tunnel junctions (AFMTJs). Through ab initio quantum transport simulations, the anisotropic transport properties of CrSb AFMTJs are systematically explored. First, the <> crystalline orientation is identified as symmetry-allowed direction for tunneling magnetoresistance (TMR) generation, yielding a spin-splitting-induced TMR ratio up to 870%, in contrast to the <> and <> directions where TMR is suppressed. Second, incorporating an MgO () barrier with favorable matching of low-decay evanescent states and interfacial reconstruction enhances the TMR ratio to ∼1700%. Third, further optimization through barrier thickening and electron doping raises the TMR ratio to ∼2900% and ∼5400%, respectively, comparable to the ideal coherent-tunneling limits theoretically predicted for Fe/MgO/Fe junctions, and the TMR ratio of the optimized junction maintains at ∼670% even under a practical 0.05 V bias. These findings establish CrSb/MgO AFMTJs as a viable pathway toward nonvolatile, high-speed, high-density antiferromagnetic memories with strong signal contrast.
{"title":"Anisotropic transport in CrSb altermagnetic tunnel junction with giant tunneling magnetoresistance","authors":"Shiqi Liu , Yingmei Zhu , Xiaobing Chen , Sheng Bi , Jie Yang , Tiejun Zhou , Bo Liu","doi":"10.1016/j.mtphys.2026.102046","DOIUrl":"10.1016/j.mtphys.2026.102046","url":null,"abstract":"<div><div>Altermagnets, a newly discovered class of collinear antiferromagnets with vanishing net magnetization yet sizable momentum-dependent spin splitting, provide a unique platform for high-performance spintronic devices. Among known altermagnets, CrSb stands out with a large ∼1 eV spin splitting near the Fermi level and a high Néel temperature above 700 K, making it particularly promising for applications in antiferromagnetic magnetic tunnel junctions (AFMTJs). Through <em>ab initio</em> quantum transport simulations, the anisotropic transport properties of CrSb AFMTJs are systematically explored. First, the <<span><math><mrow><mn>11</mn><mover><mn>2</mn><mo>‾</mo></mover><mn>0</mn></mrow></math></span>> crystalline orientation is identified as symmetry-allowed direction for tunneling magnetoresistance (TMR) generation, yielding a spin-splitting-induced TMR ratio up to 870%, in contrast to the <<span><math><mrow><mn>0001</mn></mrow></math></span>> and <<span><math><mrow><mn>10</mn><mover><mn>1</mn><mo>‾</mo></mover><mn>0</mn></mrow></math></span>> directions where TMR is suppressed. Second, incorporating an MgO (<span><math><mrow><mn>110</mn></mrow></math></span>) barrier with favorable matching of low-decay evanescent states and interfacial reconstruction enhances the TMR ratio to ∼1700%. Third, further optimization through barrier thickening and electron doping raises the TMR ratio to ∼2900% and ∼5400%, respectively, comparable to the ideal coherent-tunneling limits theoretically predicted for Fe/MgO/Fe junctions, and the TMR ratio of the optimized junction maintains at ∼670% even under a practical 0.05 V bias. These findings establish CrSb/MgO AFMTJs as a viable pathway toward nonvolatile, high-speed, high-density antiferromagnetic memories with strong signal contrast.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102046"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-07DOI: 10.1016/j.mtphys.2026.102038
Zhihui Zhang , Xiuchen Wang , Yajing Wang , Jiaxin Feng , Bobo Shi , Zhe Liu
The wide application of high-end electronic products is leading to a growing prominence of the electromagnetic pollution issue. Therefore, the exploration of lightweight, highly efficient microwave absorption materials (MAMs) constitutes a crucial step toward addressing electromagnetic interference (EMI) pollution, which is essential for ensuring the operation of electronic equipment and safeguarding human health. In recent years, structural design has garnered significant attention in microwave absorbers, and by optimizing the structure, microwave-absorbing materials can be made lightweight, thin, strong, and broad. This review comprehensively summarizes recent advancements in structural magnetic microwave-absorbing composites, focusing on typical architectures such as core-shell, porous (e.g., hollow, honeycomb, foam, gel), sandwich, and metamaterial structures. Based on the characteristics of each architecture, it explores innovations and developments in conductive polymer-based, carbon-based, and MXene-based electromagnetic composites. The comprehensive discussion highlights the advantages of heterostructured magnetic composites in microwave absorption and anticipates future challenges and broad prospects in this field.
{"title":"Progress on structured magnetic microwave absorbing composites","authors":"Zhihui Zhang , Xiuchen Wang , Yajing Wang , Jiaxin Feng , Bobo Shi , Zhe Liu","doi":"10.1016/j.mtphys.2026.102038","DOIUrl":"10.1016/j.mtphys.2026.102038","url":null,"abstract":"<div><div>The wide application of high-end electronic products is leading to a growing prominence of the electromagnetic pollution issue. Therefore, the exploration of lightweight, highly efficient microwave absorption materials (MAMs) constitutes a crucial step toward addressing electromagnetic interference (EMI) pollution, which is essential for ensuring the operation of electronic equipment and safeguarding human health. In recent years, structural design has garnered significant attention in microwave absorbers, and by optimizing the structure, microwave-absorbing materials can be made lightweight, thin, strong, and broad. This review comprehensively summarizes recent advancements in structural magnetic microwave-absorbing composites, focusing on typical architectures such as core-shell, porous (e.g., hollow, honeycomb, foam, gel), sandwich, and metamaterial structures. Based on the characteristics of each architecture, it explores innovations and developments in conductive polymer-based, carbon-based, and MXene-based electromagnetic composites. The comprehensive discussion highlights the advantages of heterostructured magnetic composites in microwave absorption and anticipates future challenges and broad prospects in this field.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102038"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-18DOI: 10.1016/j.mtphys.2026.102053
Dan Wang , Peng Zhao , Binhao Wang , Haidong Zhao , Aihua Song , Chen Chen , Tao Shen , Hang Li , Penghui Li , Jun Xu , Li Zhu , Wentao Hu , Bo Xu , Yongjun Tian
Mg3Sb2-based Zintl compounds are promising for sustainable mid-temperature thermoelectrics, yet further performance gains are often impeded by the strong coupling among electrical and thermal transport parameters. Here, we propose an Ag-enabled dual strategy to synergistically engineer electron and phonon transport in n-type Mg3Sb1.5Bi0.49Te0.01. Minute Ag incorporation on the Mg sublattice enhances carrier transport by reducing defect-related scattering; notably, HAADF-STEM/TEM analyses reveal a pronounced decrease in dislocation density and improved lattice ordering, which together contribute to an approximately twofold increase in Hall mobility. In parallel, Ag- and Bi-rich nanoprecipitates form within the matrix and along grain boundaries, respectively, creating a multiscale defect structure that drastically reduces the lattice thermal conductivity. After further tuning the carrier concentration via Te content, the optimal composition of Mg3.19Ag0.01Sb1.5Bi0.485Te0.015 achieves a peak ZT of 1.78 at 673 K and a high average ZT of 1.28 over 298–673 K. This work demonstrates that combining aliovalent doping with microstructure engineering can effectively decouple transport properties and markedly improve the thermoelectric performance of n-type Mg3Sb2-based materials.
{"title":"Synergistic carrier and phonon engineering in n-type Mg3(Sb,Bi)2 via silver Co-doping","authors":"Dan Wang , Peng Zhao , Binhao Wang , Haidong Zhao , Aihua Song , Chen Chen , Tao Shen , Hang Li , Penghui Li , Jun Xu , Li Zhu , Wentao Hu , Bo Xu , Yongjun Tian","doi":"10.1016/j.mtphys.2026.102053","DOIUrl":"10.1016/j.mtphys.2026.102053","url":null,"abstract":"<div><div>Mg<sub>3</sub>Sb<sub>2</sub>-based Zintl compounds are promising for sustainable mid-temperature thermoelectrics, yet further performance gains are often impeded by the strong coupling among electrical and thermal transport parameters. Here, we propose an Ag-enabled dual strategy to synergistically engineer electron and phonon transport in n-type Mg<sub>3</sub>Sb<sub>1.5</sub>Bi<sub>0.49</sub>Te<sub>0.01</sub>. Minute Ag incorporation on the Mg sublattice enhances carrier transport by reducing defect-related scattering; notably, HAADF-STEM/TEM analyses reveal a pronounced decrease in dislocation density and improved lattice ordering, which together contribute to an approximately twofold increase in Hall mobility. In parallel, Ag- and Bi-rich nanoprecipitates form within the matrix and along grain boundaries, respectively, creating a multiscale defect structure that drastically reduces the lattice thermal conductivity. After further tuning the carrier concentration via Te content, the optimal composition of Mg<sub>3.19</sub>Ag<sub>0.01</sub>Sb<sub>1.5</sub>Bi<sub>0.485</sub>Te<sub>0.015</sub> achieves a peak <em>ZT</em> of 1.78 at 673 K and a high average <em>ZT</em> of 1.28 over 298–673 K. This work demonstrates that combining aliovalent doping with microstructure engineering can effectively decouple transport properties and markedly improve the thermoelectric performance of n-type Mg<sub>3</sub>Sb<sub>2</sub>-based materials.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102053"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-03-04DOI: 10.1016/j.mtphys.2026.102062
Haitao Wang , Jia Wang , Yingying Lin , Hei Wong , Hiroshi Amano
This study investigates the underlying physics responsible for the formation of excellent Ohmic contacts in Mg-intercalated p-type GaN. Through comprehensive analysis of temperature-dependent current–voltage characteristics and electron energy loss spectroscopy (EELS), several previously unreported phenomena are identified. Key findings include a significant reduction in barrier height, enhanced hole concentration with increasing annealing temperature, and a transition from mixed conduction mechanisms to direct tunneling dominance in samples annealed at 550 °C or above. EELS measurements further confirm bandgap narrowing in Mg-intercalated GaN. These results are coherently explained by the formation of a two-dimensional Mg-intercalated superlattice, which induces strong internal polarization fields and elastic strain. These results give rise to four effects: (i) reduced barrier height, (ii) narrowed barrier width, (iii) enhanced hole generation, and (iv) a shallower Mg acceptor level that also functions as a trap center facilitating Poole–Frenkel emission and trap-assisted tunneling. Collectively, these effects promote direct tunneling, resulting in a significant reduction in contact resistance. This work provides new physical insights into the role of Mg intercalation, offering a promising pathway toward the development of high-performance GaN-based optoelectronic and power devices.
{"title":"Unveiling the physics of excellent ohmic contact in Mg-intercalated p-GaN","authors":"Haitao Wang , Jia Wang , Yingying Lin , Hei Wong , Hiroshi Amano","doi":"10.1016/j.mtphys.2026.102062","DOIUrl":"10.1016/j.mtphys.2026.102062","url":null,"abstract":"<div><div>This study investigates the underlying physics responsible for the formation of excellent Ohmic contacts in Mg-intercalated p-type GaN. Through comprehensive analysis of temperature-dependent current–voltage characteristics and electron energy loss spectroscopy (EELS), several previously unreported phenomena are identified. Key findings include a significant reduction in barrier height, enhanced hole concentration with increasing annealing temperature, and a transition from mixed conduction mechanisms to direct tunneling dominance in samples annealed at 550 °C or above. EELS measurements further confirm bandgap narrowing in Mg-intercalated GaN. These results are coherently explained by the formation of a two-dimensional Mg-intercalated superlattice, which induces strong internal polarization fields and elastic strain. These results give rise to four effects: (i) reduced barrier height, (ii) narrowed barrier width, (iii) enhanced hole generation, and (iv) a shallower Mg acceptor level that also functions as a trap center facilitating Poole–Frenkel emission and trap-assisted tunneling. Collectively, these effects promote direct tunneling, resulting in a significant reduction in contact resistance. This work provides new physical insights into the role of Mg intercalation, offering a promising pathway toward the development of high-performance GaN-based optoelectronic and power devices.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102062"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147359828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-18DOI: 10.1016/j.mtphys.2026.102052
Jianxin Zhao , Shuo Huang , Jingru Huang , Hao Zhang , Meng Jiang , Guocheng Sun , Long Du , Shuaiyi Zhang , Fei Lou , Maorong Wang , Xia Wang
The nonlinear absorption properties and laser modulation performance of doping-induced weakly absorbing materials are comprehensively explored, demonstrating that doping-modified weakly absorbing saturable absorbers (SAs) represent an effective class of SA for laser modulation applications. Cu-doped graphitic carbon nitride (Cu-g-C3N4) nanosheets are prepared using the ultrasonic liquid-phase exfoliation method. The modulation depths at the 1 μm and 1.3 μm wavebands, measured via the I-scan technique, are 1.21% and 1.7%, respectively, with corresponding saturation intensities of 1.1 kW/cm2 and 1.5 kW/cm2, and non-saturable losses of 1.8% and 2.4%. In passive Q-switched (PQS) experiments operating at 1 μm and 1.3 μm, the maximum repetition rates reach to 3.77 MHz and 2.77 MHz, accompanied by pulse widths of 47.8 ns and 41.1 ns, respectively. To the best of our knowledge, this represents the highest repetition rate reported to date for PQS at these wavebands, attributed to the low saturation intensity and low modulation depth of the Cu-g-C3N4 SA. For passively mode-locked lasers operating at 1 μm and 1.3 μm, the narrowest pulse widths are achieved using Nd-ion-doped single-crystal gain media, benefiting from the enhanced intracavity power density caused by the low non-saturable losses of Cu-g-C3N4. Specifically, the continuous-wave mode-locked (CWML) lasers deliver pulse widths of 3.1 ps and 4.7 ps at 1 μm and 1.3 μm, with repetition rates of 62.1 MHz and 71 MHz, respectively. Based on weakly absorbing SAs induced by controlled doping, this work provides an effective strategy for facilitating ultrafast pulse width compression in solid-state lasers.
{"title":"Cu-doped graphitic carbon nitride for ultrafast lasing at 1.0 and 1.3 μm","authors":"Jianxin Zhao , Shuo Huang , Jingru Huang , Hao Zhang , Meng Jiang , Guocheng Sun , Long Du , Shuaiyi Zhang , Fei Lou , Maorong Wang , Xia Wang","doi":"10.1016/j.mtphys.2026.102052","DOIUrl":"10.1016/j.mtphys.2026.102052","url":null,"abstract":"<div><div>The nonlinear absorption properties and laser modulation performance of doping-induced weakly absorbing materials are comprehensively explored, demonstrating that doping-modified weakly absorbing saturable absorbers (SAs) represent an effective class of SA for laser modulation applications. Cu-doped graphitic carbon nitride (Cu-g-C<sub>3</sub>N<sub>4</sub>) nanosheets are prepared using the ultrasonic liquid-phase exfoliation method. The modulation depths at the 1 μm and 1.3 μm wavebands, measured via the I-scan technique, are 1.21% and 1.7%, respectively, with corresponding saturation intensities of 1.1 kW/cm<sup>2</sup> and 1.5 kW/cm<sup>2</sup>, and non-saturable losses of 1.8% and 2.4%. In passive Q-switched (PQS) experiments operating at 1 μm and 1.3 μm, the maximum repetition rates reach to 3.77 MHz and 2.77 MHz, accompanied by pulse widths of 47.8 ns and 41.1 ns, respectively. To the best of our knowledge, this represents the highest repetition rate reported to date for PQS at these wavebands, attributed to the low saturation intensity and low modulation depth of the Cu-g-C<sub>3</sub>N<sub>4</sub> SA. For passively mode-locked lasers operating at 1 μm and 1.3 μm, the narrowest pulse widths are achieved using Nd-ion-doped single-crystal gain media, benefiting from the enhanced intracavity power density caused by the low non-saturable losses of Cu-g-C<sub>3</sub>N<sub>4</sub>. Specifically, the continuous-wave mode-locked (CWML) lasers deliver pulse widths of 3.1 ps and 4.7 ps at 1 μm and 1.3 μm, with repetition rates of 62.1 MHz and 71 MHz, respectively. Based on weakly absorbing SAs induced by controlled doping, this work provides an effective strategy for facilitating ultrafast pulse width compression in solid-state lasers.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102052"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-05DOI: 10.1016/j.mtphys.2026.102045
Yingzhengsheng Huang , Wei Quan , Qiyao Geng , Longfei Ma , Qiang Zheng , Juan Du
Hard-soft magnetic nanocomposite magnets hold great promise for next-generation permanent magnets due to their ultrahigh theoretical maximum energy product ((BH)max) and low-cost, while the low coercivity (Hc) of the currently fabricated SmCo/FeCo nanocomposites limits their performance. In this work, two types of microstructures with and without direct contacts between soft and hard magnetic phases in nanocomposites were designed and analyzed by micromagnetic simulations. The results showed that the directly contact nanocomposites exhibit a larger magnetic domain size and stronger interphase exchange coupling, facilitating magnetization of the hard magnetic phase and impeding reversal of the soft magnetic phase during magnetization and demagnetization processes. The simulation results were validated through the fabrication of SmCo/FeCo nanocomposites featuring an in-situ formed semi-coherent soft/hard magnetic phase. This nanocomposite was synthesized by crystallizing an as-milled amorphous Sm-Co-Fe precursor derived from a Sm-Co-Fe ingot. A reference magnet of without soft/hard magnetic phase contact, i.e. with amorphous-separated between two phases was fabricated by crystallizing amorphous-nanocrystalline precursor from co-milling Sm-Co alloy and Fe powders. Comparatively, the semi-coherent contact nanocomposite magnet showed a 28% increase in Hc and an 18% improvement in (BH)max. Microstructural analysis revealed that the semi-coherent structure forms through synchronous crystallization driven by a compositional gradient. Micromagnetic simulations, Henkel curves, and in-situ domain observations confirmed that enhanced exchange coupling is the origin of Hc enhancement. This work provides a viable microstructural regulation strategy for developing high-performance nanocomposite magnets.
{"title":"Magnetic hardening via in-situ formed semi-coherent soft/hard magnetic phases in SmCo/FeCo nanocomposites","authors":"Yingzhengsheng Huang , Wei Quan , Qiyao Geng , Longfei Ma , Qiang Zheng , Juan Du","doi":"10.1016/j.mtphys.2026.102045","DOIUrl":"10.1016/j.mtphys.2026.102045","url":null,"abstract":"<div><div>Hard-soft magnetic nanocomposite magnets hold great promise for next-generation permanent magnets due to their ultrahigh theoretical maximum energy product ((<em>BH</em>)<sub>max</sub>) and low-cost, while the low coercivity (<em>H</em><sub>c</sub>) of the currently fabricated SmCo/FeCo nanocomposites limits their performance. In this work, two types of microstructures with and without direct contacts between soft and hard magnetic phases in nanocomposites were designed and analyzed by micromagnetic simulations. The results showed that the directly contact nanocomposites exhibit a larger magnetic domain size and stronger interphase exchange coupling, facilitating magnetization of the hard magnetic phase and impeding reversal of the soft magnetic phase during magnetization and demagnetization processes. The simulation results were validated through the fabrication of SmCo/FeCo nanocomposites featuring an in-situ formed semi-coherent soft/hard magnetic phase. This nanocomposite was synthesized by crystallizing an as-milled amorphous Sm-Co-Fe precursor derived from a Sm-Co-Fe ingot. A reference magnet of without soft/hard magnetic phase contact, i.e. with amorphous-separated between two phases was fabricated by crystallizing amorphous-nanocrystalline precursor from co-milling Sm-Co alloy and Fe powders. Comparatively, the semi-coherent contact nanocomposite magnet showed a 28% increase in <em>H</em><sub>c</sub> and an 18% improvement in (<em>BH</em>)<sub>max</sub>. Microstructural analysis revealed that the semi-coherent structure forms through synchronous crystallization driven by a compositional gradient. Micromagnetic simulations, Henkel curves, and in-situ domain observations confirmed that enhanced exchange coupling is the origin of <em>H</em><sub>c</sub> enhancement. This work provides a viable microstructural regulation strategy for developing high-performance nanocomposite magnets.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"62 ","pages":"Article 102045"},"PeriodicalIF":9.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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