Lichao Wang, Yang Li, Xindi Li, Yiwei Zhu, Jian Kang, Le Zhang, Cen Shao, Jun Zou
A high‐power white laser source is prepared by using a 455 nm blue laser to excite YAG:Ce ceramics. To achieve high‐power output, a water‐cooling device is used to reduce the operating temperature of ceramics. The luminescence properties of laser‐excited phosphor ceramics are studied under different blue excitation power and different irradiation time. The experimental results show that the luminous flux of phosphor ceramics excited by the blue laser increases linearly with the increase of blue laser power, depending on the heat dissipation of the water‐cooling device. When the blue laser power increases to 73.1 W, the phosphor ceramics do not reach the luminescence saturation state. The luminous flux of phosphor ceramics excited by 73.1 W blue laser is stable within 60 min. The maximum luminous flux is 8094 lm, and the maximum working temperature of the ceramics is 110 °C. The experimental results show that water‐cooling packages are an effective means to realize high‐power white laser sources.
利用 455 nm 的蓝色激光激发 YAG:Ce 陶瓷，制备出高功率白光激光源。为了实现高功率输出，使用了水冷装置来降低陶瓷的工作温度。研究了不同蓝光激发功率和不同照射时间下激光激发荧光粉陶瓷的发光特性。实验结果表明，蓝光激光激发荧光粉陶瓷的光通量随蓝光激光功率的增加而线性增加，这取决于水冷装置的散热情况。当蓝色激光功率增加到 73.1 W 时，荧光粉陶瓷并没有达到发光饱和状态。在 73.1 W 蓝色激光的激励下，荧光粉陶瓷的光通量在 60 分钟内保持稳定。最大光通量为 8094 lm，陶瓷的最高工作温度为 110 °C。实验结果表明，水冷封装是实现高功率白光激光源的有效手段。
{"title":"Study on Thermal and Luminescence Properties of YAG:Ce Ceramics Excited by High‐Power Fiber Laser with the Condition of a Water‐Cooling Package","authors":"Lichao Wang, Yang Li, Xindi Li, Yiwei Zhu, Jian Kang, Le Zhang, Cen Shao, Jun Zou","doi":"10.1002/pssr.202400143","DOIUrl":"https://doi.org/10.1002/pssr.202400143","url":null,"abstract":"A high‐power white laser source is prepared by using a 455 nm blue laser to excite YAG:Ce ceramics. To achieve high‐power output, a water‐cooling device is used to reduce the operating temperature of ceramics. The luminescence properties of laser‐excited phosphor ceramics are studied under different blue excitation power and different irradiation time. The experimental results show that the luminous flux of phosphor ceramics excited by the blue laser increases linearly with the increase of blue laser power, depending on the heat dissipation of the water‐cooling device. When the blue laser power increases to 73.1 W, the phosphor ceramics do not reach the luminescence saturation state. The luminous flux of phosphor ceramics excited by 73.1 W blue laser is stable within 60 min. The maximum luminous flux is 8094 lm, and the maximum working temperature of the ceramics is 110 °C. The experimental results show that water‐cooling packages are an effective means to realize high‐power white laser sources.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hao Ding, Jingyu Hou, Kun Zhai, Xin Gao, Zhiwei Shen, Junquan Huang, Bingchao Yang, Feng Ke, Congpu Mu, Fusheng Wen, Jianyong Xiang, Bochong Wang, Tianyu Xue, Anmin Nie, Xiaobing Liu, Lin Wang, Xiang‐Feng Zhou, Zhongyuan Liu
Tuning interlayer interactions offer an alternative approach to access novel electronic structure and intriguing physical properties in layered materials. Here, the emergence of a new form of superconductivity in two‐dimensional (2D) binary phosphides by strengthening the interlayer coupling with lattice compression is reported. Electrical transport measurements show strong evidence of superconductivity in InP3 with the highest critical temperature (Tc) of 9.5 K at 45.1 GPa. Raman and X‐ray diffraction (XRD) measurements indicate that the interlayer interactions are dramatically modulated under compression, along with the deformation of local In–P bipyramid structure and reduction of the interlayer distances, which eventually results in the formation of In–P bonds between neighboring In–P bipyramids and a Rm to Cmcm structural transition. First‐principles density functional theory (DFT) calculations reveal that pressure enhances the interlayer interactions, which increases the density of states (DOS) near the Fermi surface (N(EF)) and strengthens the electron–phonon coupling. Consequently, this favors the occurrence of superconductivity in compressed InP3. This study not only introduces a new superconductivity phase with enhanced electron–phonon coupling in binary phosphides, but also provides a platform for exploring the pressure effect on interlayer interactions in material systems with corrugated layered structure.
{"title":"Emergence of Superconductivity in Indium Triphosphate via Pressure‐Tuned Interlayer Bond Formation","authors":"Hao Ding, Jingyu Hou, Kun Zhai, Xin Gao, Zhiwei Shen, Junquan Huang, Bingchao Yang, Feng Ke, Congpu Mu, Fusheng Wen, Jianyong Xiang, Bochong Wang, Tianyu Xue, Anmin Nie, Xiaobing Liu, Lin Wang, Xiang‐Feng Zhou, Zhongyuan Liu","doi":"10.1002/pssr.202400206","DOIUrl":"https://doi.org/10.1002/pssr.202400206","url":null,"abstract":"Tuning interlayer interactions offer an alternative approach to access novel electronic structure and intriguing physical properties in layered materials. Here, the emergence of a new form of superconductivity in two‐dimensional (2D) binary phosphides by strengthening the interlayer coupling with lattice compression is reported. Electrical transport measurements show strong evidence of superconductivity in InP<jats:sub>3</jats:sub> with the highest critical temperature (<jats:italic>T</jats:italic><jats:sub>c</jats:sub>) of 9.5 K at 45.1 GPa. Raman and X‐ray diffraction (XRD) measurements indicate that the interlayer interactions are dramatically modulated under compression, along with the deformation of local In–P bipyramid structure and reduction of the interlayer distances, which eventually results in the formation of In–P bonds between neighboring In–P bipyramids and a <jats:italic>R</jats:italic><jats:italic>m</jats:italic> to <jats:italic>Cmcm</jats:italic> structural transition. First‐principles density functional theory (DFT) calculations reveal that pressure enhances the interlayer interactions, which increases the density of states (DOS) near the Fermi surface (<jats:italic>N</jats:italic>(<jats:italic>E</jats:italic><jats:sub>F</jats:sub>)) and strengthens the electron–phonon coupling. Consequently, this favors the occurrence of superconductivity in compressed InP<jats:sub>3</jats:sub>. This study not only introduces a new superconductivity phase with enhanced electron–phonon coupling in binary phosphides, but also provides a platform for exploring the pressure effect on interlayer interactions in material systems with corrugated layered structure.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the interaction of various environmental oxidizing agents is important in determining the physical and chemical properties of 2D materials. Its impact holds great significance for the practical application of these materials in nanoscale devices functioning under ambient conditions. This study delves into the influence of O2 and O3 exposure on the structural and electronic characteristics of the C2N monolayer, focusing on the kinetics of adsorption and dissociation reactions. Employing first‐principles density‐functional theory calculations alongside climbing image nudged elastic band calculations, it is observed that the monolayer exhibits resistance to ozonation, evidenced by energy barriers of 0.56 eV. These processes are accompanied by the formation of COC groups. Furthermore, the dissociation mechanism involves charge transfers from the monolayer to the molecules. Notably, the dissociated configurations demonstrate higher bandgaps compared to the pristine monolayer, attributed to robust CO hybridization. These findings suggest the robustness of C2N monolayers against oxygen/ozone exposures, ensuring stability for devices incorporating these materials.
{"title":"Unveiling the Reactivity of Oxygen and Ozone on C2N Monolayer","authors":"Soumendra Kumar Das, Lokanath Patra, Prasanjit Samal, Pratap Kumar Sahoo","doi":"10.1002/pssr.202400148","DOIUrl":"https://doi.org/10.1002/pssr.202400148","url":null,"abstract":"Understanding the interaction of various environmental oxidizing agents is important in determining the physical and chemical properties of 2D materials. Its impact holds great significance for the practical application of these materials in nanoscale devices functioning under ambient conditions. This study delves into the influence of O<jats:sub>2</jats:sub> and O<jats:sub>3</jats:sub> exposure on the structural and electronic characteristics of the C<jats:sub>2</jats:sub>N monolayer, focusing on the kinetics of adsorption and dissociation reactions. Employing first‐principles density‐functional theory calculations alongside climbing image nudged elastic band calculations, it is observed that the monolayer exhibits resistance to ozonation, evidenced by energy barriers of 0.56 eV. These processes are accompanied by the formation of COC groups. Furthermore, the dissociation mechanism involves charge transfers from the monolayer to the molecules. Notably, the dissociated configurations demonstrate higher bandgaps compared to the pristine monolayer, attributed to robust CO hybridization. These findings suggest the robustness of C<jats:sub>2</jats:sub>N monolayers against oxygen/ozone exposures, ensuring stability for devices incorporating these materials.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Minje Kim, Sunjae Kim, Ji‐Hyeon Park, Hyeon Gu Cho, Se Hoon Gihm, Dae‐Woo Jeon, Wan Sik Hwang
This study explores the potential of 700‐nm‐thick heteroepitaxial α‐Ga2O3 thin films on c‐plane sapphire substrates for X‐ray detector applications. The crystal quality and optical bandgap of the heteroepitaxial α‐Ga2O3 thin films are comparable to those of high‐quality α‐Ga2O3 thin films. The α‐Ga2O3 thin film X‐ray detector with a metal–semiconductor–metal structure exhibits a charge neutral point shift, resulting in a short‐circuit current density of 9.07 nA cm−2 and an open‐circuit voltage of –1.2 V. The detector achieves the highest signal‐to‐noise ratio of 973 at 0 V, while the maximum sensitivity (14.7 μC Gyair−1 cm−2) occurs at 10 V. The proposed X‐ray detector demonstrates a reliable transient response and long‐term robustness, suggesting the promise of heteroepitaxial α‐Ga2O3 for low‐cost, high‐quality, large‐area X‐ray detectors.
本研究探讨了在 c 平面蓝宝石基底上的 700 纳米厚异质外延 α-Ga2O3 薄膜在 X 射线探测器中的应用潜力。异质外延 α-Ga2O3 薄膜的晶体质量和光带隙与高质量 α-Ga2O3 薄膜相当。金属-半导体-金属结构的α-Ga2O3 薄膜 X 射线探测器表现出电荷中性点偏移，其短路电流密度为 9.07 nA cm-2，开路电压为-1.2 V。所提出的 X 射线探测器具有可靠的瞬态响应和长期稳健性，表明异质外延 α-Ga2O3 在低成本、高质量、大面积 X 射线探测器方面大有可为。
{"title":"Heteroepitaxial α‐Ga2O3 Thin Film‐Based X‐Ray Detector with Metal–Semiconductor–Metal Structure","authors":"Minje Kim, Sunjae Kim, Ji‐Hyeon Park, Hyeon Gu Cho, Se Hoon Gihm, Dae‐Woo Jeon, Wan Sik Hwang","doi":"10.1002/pssr.202400193","DOIUrl":"https://doi.org/10.1002/pssr.202400193","url":null,"abstract":"This study explores the potential of 700‐nm‐thick heteroepitaxial α‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> thin films on c‐plane sapphire substrates for X‐ray detector applications. The crystal quality and optical bandgap of the heteroepitaxial α‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> thin films are comparable to those of high‐quality α‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> thin films. The α‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> thin film X‐ray detector with a metal–semiconductor–metal structure exhibits a charge neutral point shift, resulting in a short‐circuit current density of 9.07 nA cm<jats:sup>−2</jats:sup> and an open‐circuit voltage of –1.2 V. The detector achieves the highest signal‐to‐noise ratio of 973 at 0 V, while the maximum sensitivity (14.7 μC Gy<jats:sub>air</jats:sub><jats:sup>−1</jats:sup> cm<jats:sup>−2</jats:sup>) occurs at 10 V. The proposed X‐ray detector demonstrates a reliable transient response and long‐term robustness, suggesting the promise of heteroepitaxial α‐Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> for low‐cost, high‐quality, large‐area X‐ray detectors.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sophie L. Pain, Anup Yadav, David Walker, Nicholas E. Grant, John D. Murphy
Hafnium oxide (HfOx) films grown by atomic layer deposition (ALD) have recently been demonstrated to provide high‐quality silicon surface passivation. Reports have suggested that changing the composition of the hafnium‐containing precursor can enable films of both charge polarities to be produced. Herein, the passivation quality of hafnium oxide grown with metal amide precursors and a tetrakis(ethylmethylamido)hafnium (TEMAHf) precursor is examined, considering film charge polarity, chemical‐ and field‐based passivation effects, and film crystallinity. Throughout, the properties of TEMAHf‐HfOx are benchmarked against that of hafnium oxide grown with a tetrakis(dimethylamido)hafnium precursor. It is found that precursor choice has no influence on the fixed negative charge polarity (of order −1012 q cm−2) of HfOx films grown via plasma‐enhanced ALD. TEMAHf‐HfOx passivation is influenced by post‐deposition annealing temperature and can passivate with a surface recombination velocity ≤3 cm s−1 on n‐type silicon, compared to surface recombination velocities ≤11 cm s−1 for TDMAHf‐HfOx of a similar thickness.
通过原子层沉积（ALD）技术生长的氧化铪（HfOx）薄膜最近被证明可以提供高质量的硅表面钝化。有报告指出，改变含铪前驱体的成分可以生产出两种电荷极性的薄膜。在此，考虑到薄膜的电荷极性、化学和电场钝化效应以及薄膜的结晶度，研究了用金属酰胺前驱体和四(乙基甲基氨基)铪（TEMAHf）前驱体生长的氧化铪的钝化质量。在整个研究过程中，TEMAHf-HfOx 的特性与使用四（二甲基氨基）铪前驱体生长的氧化铪的特性进行了比较。结果发现，前驱体的选择对通过等离子体增强 ALD 生长的氧化铪薄膜的固定负电荷极性（数量级为 -1012 q cm-2）没有影响。TEMAHf-HfOx 的钝化受沉积后退火温度的影响，在 n 型硅上的表面钝化重组速度≤3 cm s-1，而类似厚度的 TDMAHf-HfOx 的表面重组速度≤11 cm s-1。
{"title":"Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection","authors":"Sophie L. Pain, Anup Yadav, David Walker, Nicholas E. Grant, John D. Murphy","doi":"10.1002/pssr.202400202","DOIUrl":"https://doi.org/10.1002/pssr.202400202","url":null,"abstract":"Hafnium oxide (HfO<jats:sub><jats:italic>x</jats:italic></jats:sub>) films grown by atomic layer deposition (ALD) have recently been demonstrated to provide high‐quality silicon surface passivation. Reports have suggested that changing the composition of the hafnium‐containing precursor can enable films of both charge polarities to be produced. Herein, the passivation quality of hafnium oxide grown with metal amide precursors and a tetrakis(ethylmethylamido)hafnium (TEMAHf) precursor is examined, considering film charge polarity, chemical‐ and field‐based passivation effects, and film crystallinity. Throughout, the properties of TEMAHf‐HfO<jats:sub><jats:italic>x</jats:italic></jats:sub> are benchmarked against that of hafnium oxide grown with a tetrakis(dimethylamido)hafnium precursor. It is found that precursor choice has no influence on the fixed negative charge polarity (of order −10<jats:sup>12</jats:sup> q cm<jats:sup>−2</jats:sup>) of HfO<jats:sub><jats:italic>x</jats:italic></jats:sub> films grown via plasma‐enhanced ALD. TEMAHf‐HfO<jats:sub><jats:italic>x</jats:italic></jats:sub> passivation is influenced by post‐deposition annealing temperature and can passivate with a surface recombination velocity ≤3 cm s<jats:sup>−1</jats:sup> on n‐type silicon, compared to surface recombination velocities ≤11 cm s<jats:sup>−1</jats:sup> for TDMAHf‐HfO<jats:sub><jats:italic>x</jats:italic></jats:sub> of a similar thickness.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maya N. Nair, Irene Palacio, Yoshiyuki Ohtsubo, Amina Taleb‐Ibrahimi, Enrique G. Michel, Arantzazu Mascaraque, Antonio Tejeda
{"title":"Electronic Structure Evolution in the Temperature Range of Metal–Insulator Transitions on Sn/Ge(111)","authors":"Maya N. Nair, Irene Palacio, Yoshiyuki Ohtsubo, Amina Taleb‐Ibrahimi, Enrique G. Michel, Arantzazu Mascaraque, Antonio Tejeda","doi":"10.1002/pssr.202470020","DOIUrl":"https://doi.org/10.1002/pssr.202470020","url":null,"abstract":"","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinsong Jiang, Wei Hong, Tingyu Liu, Wenqi Song, Liying Yang
The behavior of self‐trapped holes (STH) adjacent to a H vacancy in K (KDP) crystals is investigated using the DFT + U and hybrid density functional calculations. The calculated results reveal that STH is located on one O atom near and introduces new defect energy levels in the bandgap. The hole tends to be self‐trapped and is more stable at room temperature along with partial lattice distortions. The STH in KDP crystals has a large migration barrier energy, implying a small mobility rate. The optical properties associated with STH are calculated and the emission peak is predicted to be 2.55 eV (487 nm) and the absorption peak to be 4.58 eV (271 nm), which is in good agreement with the experimental results.
利用 DFT + U 和混合密度泛函计算研究了 K (KDP) 晶体中 H 空位附近的自捕空穴 (STH) 的行为。计算结果显示，STH 位于一个 O 原子附近，并在带隙中引入了新的缺陷能级。空穴倾向于自俘获，并且在室温下更加稳定，同时存在部分晶格畸变。KDP 晶体中的 STH 具有较大的迁移势垒能，这意味着迁移率较小。通过计算与 STH 相关的光学特性，预测其发射峰值为 2.55 eV（487 nm），吸收峰值为 4.58 eV（271 nm），这与实验结果非常吻合。
{"title":"Study of Migration Behavior and Optical Properties of Self‐Trapped Hole by Hydrogen Vacancy in KH2PO4 Crystal","authors":"Jinsong Jiang, Wei Hong, Tingyu Liu, Wenqi Song, Liying Yang","doi":"10.1002/pssr.202400184","DOIUrl":"https://doi.org/10.1002/pssr.202400184","url":null,"abstract":"The behavior of self‐trapped holes (STH) adjacent to a H vacancy in K (KDP) crystals is investigated using the DFT + <jats:italic>U</jats:italic> and hybrid density functional calculations. The calculated results reveal that STH is located on one O atom near and introduces new defect energy levels in the bandgap. The hole tends to be self‐trapped and is more stable at room temperature along with partial lattice distortions. The STH in KDP crystals has a large migration barrier energy, implying a small mobility rate. The optical properties associated with STH are calculated and the emission peak is predicted to be 2.55 eV (487 nm) and the absorption peak to be 4.58 eV (271 nm), which is in good agreement with the experimental results.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marie Darcheville, Anne‐Lise Adenot‐Engelvin, Christophe Boscher, Jean‐Marc Grenèche, Christophe Lefèvre, Jérôme Robert, Ovidiu Ersen, José Maria Gonzalez Calbet, Maria Luisa Ruiz Gonzalez, André Thiaville, Clément Sanchez
Zn‐substituted iron oxide nanoparticles of ≈5 nm in diameter are synthetized by a microwave‐assisted thermal decomposition method. The addition of ethylene glycol results in a size increase to 22 nm. Cationic disorder has been observed by electron energy loss spectroscopy–scanning transmission electron microscopy. Using Mössbauer spectrometry combined with Rietveld analysis, the complete cationic and vacancies repartition in the lattice is determined, as well as the canting of magnetic moments. This allows the magnetic moment to be calculated, in good agreement with that measured. The alternating current magnetic susceptibility is modeled by the Néel–Brown and the Coffey models, showing some discrepancy between these two approaches which is discussed. The largest particles show a complex morphology involving an oriented attachment mechanism of smaller units. Their cationic disorder and internal porosity have been evidenced and quantified, and the work shows that despite these defects they behave rather as magnetically blocked nanoparticles.
{"title":"Magnetism of Iron Oxide Nanoparticles: From Atomic Order to Complexity at the Mesoscopic Scale","authors":"Marie Darcheville, Anne‐Lise Adenot‐Engelvin, Christophe Boscher, Jean‐Marc Grenèche, Christophe Lefèvre, Jérôme Robert, Ovidiu Ersen, José Maria Gonzalez Calbet, Maria Luisa Ruiz Gonzalez, André Thiaville, Clément Sanchez","doi":"10.1002/pssr.202400059","DOIUrl":"https://doi.org/10.1002/pssr.202400059","url":null,"abstract":"Zn‐substituted iron oxide nanoparticles of ≈5 nm in diameter are synthetized by a microwave‐assisted thermal decomposition method. The addition of ethylene glycol results in a size increase to 22 nm. Cationic disorder has been observed by electron energy loss spectroscopy–scanning transmission electron microscopy. Using Mössbauer spectrometry combined with Rietveld analysis, the complete cationic and vacancies repartition in the lattice is determined, as well as the canting of magnetic moments. This allows the magnetic moment to be calculated, in good agreement with that measured. The alternating current magnetic susceptibility is modeled by the Néel–Brown and the Coffey models, showing some discrepancy between these two approaches which is discussed. The largest particles show a complex morphology involving an oriented attachment mechanism of smaller units. Their cationic disorder and internal porosity have been evidenced and quantified, and the work shows that despite these defects they behave rather as magnetically blocked nanoparticles.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141882781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report the growth of AlBN/β‐Nb2N nitride epitaxial heterostructures in which the AlBN is ferroelectric, and β‐Nb2N with metallic resistivity ≈40 μ at 300 K becomes superconducting below TC ≈ 0.5 K. Using nitrogen plasma molecular beam epitaxy, we grow hexagonal β‐Nb2N films on c‐plane Al2O3 substrates, followed by wurtzite AlBN. The AlBN is in epitaxial registry and rotationally aligned with the β‐Nb2N, and the hexagonal lattices of both nitride layers make angles of 30° with the hexagonal lattice of the Al2O3 substrate. The B composition of the AlBN layer is varied from 0 to 14.7%. It is found to depend weakly on the B flux, but increases strongly with decreasing growth temperature, indicating a reaction rate‐controlled growth. The increase in B content causes a non‐monotonic change in the a‐lattice constant and a monotonic decrease in the c‐lattice constant of AlBN. Sharp, abrupt epitaxial AlBN/β‐Nb2N/Al2O3 heterojunction interfaces and close symmetry matching are observed by transmission electron microscopy. The observation of ferroelectricity and superconductivity in epitaxial nitride heterostructures opens avenues for novel electronic and quantum devices.
{"title":"Epitaxial AlBN/β‐Nb2N Ferroelectric/Superconductor Heterostructures","authors":"Chandrashekhar Savant, Thai‐Son Nguyen, Saurabh Vishwakarma, Joongwon Lee, Anand Ithepalli, Yu‐Hsin Chen, Kazuki Nomoto, Farhan Rana, David J. Smith, Huili Grace Xing, Debdeep Jena","doi":"10.1002/pssr.202400157","DOIUrl":"https://doi.org/10.1002/pssr.202400157","url":null,"abstract":"We report the growth of AlBN/β‐Nb<jats:sub>2</jats:sub>N nitride epitaxial heterostructures in which the AlBN is ferroelectric, and β‐Nb<jats:sub>2</jats:sub>N with metallic resistivity ≈40 μ at 300 K becomes superconducting below <jats:italic>T</jats:italic><jats:sub>C</jats:sub> ≈ 0.5 K. Using nitrogen plasma molecular beam epitaxy, we grow hexagonal β‐Nb<jats:sub>2</jats:sub>N films on c‐plane Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> substrates, followed by wurtzite AlBN. The AlBN is in epitaxial registry and rotationally aligned with the β‐Nb<jats:sub>2</jats:sub>N, and the hexagonal lattices of both nitride layers make angles of 30° with the hexagonal lattice of the Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> substrate. The B composition of the AlBN layer is varied from 0 to 14.7%. It is found to depend weakly on the B flux, but increases strongly with decreasing growth temperature, indicating a reaction rate‐controlled growth. The increase in B content causes a non‐monotonic change in the a‐lattice constant and a monotonic decrease in the c‐lattice constant of AlBN. Sharp, abrupt epitaxial AlBN/β‐Nb<jats:sub>2</jats:sub>N/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> heterojunction interfaces and close symmetry matching are observed by transmission electron microscopy. The observation of ferroelectricity and superconductivity in epitaxial nitride heterostructures opens avenues for novel electronic and quantum devices.","PeriodicalId":54619,"journal":{"name":"Physica Status Solidi-Rapid Research Letters","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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