Pub Date : 2026-02-01Epub Date: 2025-11-24DOI: 10.1016/j.ssc.2025.116252
Yves Noat , Alain Mauger , William Sacks
In this article we show that the condensation mechanism in cuprates involves the strong coupling of the condensate to pairon excited states. We present an accessible formalism that significantly extends our previous work, providing a theoretical basis for the energy-dependent gap function . The latter is proportional to the effective spin exchange energy, , with no retardation effects, such as the case of spin-fluctuation or phonon mediated couplings. The fundamental parameters of the superconducting (SC) state are the condensation energy per pair, , and the antinodal energy gap, , which are quantitatively extracted by fitting the cuprate quasiparticle spectrum from tunneling experiments.
An explicit formula for the critical temperature is also derived in the model. Valid for any doping, we find to be proportional to , and not the gap , in sharp contrast to conventional SC. The numerical factor originates from pair excitations of the condensate, following Bose statistics, with a mini-gap meV in the excitation spectrum. These results strongly suggest that the same ‘all-electron’ mechanism is at work all along the -dome.
{"title":"Condensation mechanism of high-Tc cuprates: The key role of pairon excitations","authors":"Yves Noat , Alain Mauger , William Sacks","doi":"10.1016/j.ssc.2025.116252","DOIUrl":"10.1016/j.ssc.2025.116252","url":null,"abstract":"<div><div>In this article we show that the condensation mechanism in cuprates involves the strong coupling of the condensate to pairon excited states. We present an accessible formalism that significantly extends our previous work, providing a theoretical basis for the energy-dependent gap function <span><math><mrow><mi>Δ</mi><mrow><mo>(</mo><mi>E</mi><mo>)</mo></mrow></mrow></math></span>. The latter is proportional to the effective spin exchange energy, <span><math><msub><mrow><mi>J</mi></mrow><mrow><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub></math></span>, with no retardation effects, such as the case of spin-fluctuation or phonon mediated couplings. The fundamental parameters of the superconducting (SC) state are the condensation energy per pair, <span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, and the antinodal energy gap, <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, which are quantitatively extracted by fitting the cuprate quasiparticle spectrum from tunneling experiments.</div><div>An explicit formula for the critical temperature is also derived in the model. Valid for any doping, we find <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> to be proportional to <span><math><msub><mrow><mi>β</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, and not the gap <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, in sharp contrast to conventional SC. The numerical factor <span><math><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>/</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>B</mi></mrow></msub><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>≃</mo><mn>2</mn><mo>.</mo><mn>24</mn></mrow></math></span> originates from pair excitations of the condensate, following Bose statistics, with a mini-gap <span><math><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>M</mi></mrow></msub><mo>≃</mo><mn>1</mn><mspace></mspace></mrow></math></span>meV in the excitation spectrum. These results strongly suggest that the same ‘all-electron’ mechanism is at work all along the <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>-dome.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"408 ","pages":"Article 116252"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621823","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}
Pub Date : 2026-02-01Epub Date: 2025-11-24DOI: 10.1016/j.ssc.2025.116261
Vusala Nabi Jafarova, Kh.O. Sadig, A.A. Hadiyeva, J.R. Sultanova
<div><div>The electronic and magnetic properties of silver-doped single-walled ZnO nanotubes (SW-ZnO:AgNTs) with (6,0) chirality were investigated using density functional theory (DFT). The structural model was constructed by substituting one Zn atom with an Ag atom in a (6,0) ZnO nanotube containing 12 Zn and 12 O atoms. For single substitution, one Zn atom was replaced by one Ag atom, corresponding to <em>x</em> ≈ 0.08 in Ag<sub><em>x</em></sub>Zn<sub>1-<em>x</em></sub>O. For double substitution, two Zn atoms were replaced by Ag atoms (<em>x</em> ≈ 0.16), placed at non-adjacent Zn sites to reduce artificial interaction. In the double substitution configuration, Ag atoms were positioned at a minimum distance of ∼6.38 <em>Å</em> to study the effect of non-interacting dopants on the electronic and magnetic properties. All structures were fully relaxed using a force convergence criterion of 0.01 eV/Å. Spin-polarized DFT calculations were performed for all configurations to capture the magnetic response induced by Ag doping. Our simulations, performed using the Quantum ATK software, reveal that Ag doping induces notable changes in the electronic structure, including a reduction of the band gap and the emergence of spin polarization.</div><div>For pristine SW-ZnONTs, we obtain a direct band gap of 3.10 eV, confirming their semiconducting and non-magnetic nature. Ag doping breaks this symmetry and introduces strong spin polarization. In the singly doped system, the spin-up channel retains a reduced band gap of about 2.5 eV, while the spin-down channel becomes almost gapless at the Fermi level, indicating clear half-metallic behavior. Double Ag doping preserves this asymmetry and further enhances spin polarization, with a slightly smaller spin-up band gap than in the singly doped case. Mulliken analysis reveals a total magnetic moment of approximately 1.0 <em>μ</em><sub><em>B</em></sub> for single doping, originating mainly from the oxygen atoms (∼0.8 <em>μ</em><sub><em>B</em></sub>) surrounding the Ag dopant and a smaller contribution from Ag itself (∼0.2 <em>μ</em><sub><em>B</em></sub>). Total energy calculations comparing ferromagnetic and antiferromagnetic configurations show that the FM phase is energetically more favorable by 0.048 eV, confirming the stability of ferromagnetism in the doped nanotube. Quantitative analysis of the bound magnetic polaron (BMP) characteristics reveals effective BMP radii of ∼2.2 <em>Å</em> and a significant increase in BMP number density from single to double Ag doping, confirming a percolative BMP-mediated mechanism that stabilizes long-range ferromagnetism above room temperature. The estimated Curie temperature (≈370 <em>K</em>) confirms that the singly Ag-doped SW-ZnONT maintains stable ferromagnetic ordering above room temperature, highlighting its potential for spintronic devices. The structural integrity is preserved post-doping, with minimal atomic distortion, low residual forces, and negligible stress values,
{"title":"Prediction of electronic and ferromagnetic characteristics OF ZnO:Ag nanotubes","authors":"Vusala Nabi Jafarova, Kh.O. Sadig, A.A. Hadiyeva, J.R. Sultanova","doi":"10.1016/j.ssc.2025.116261","DOIUrl":"10.1016/j.ssc.2025.116261","url":null,"abstract":"<div><div>The electronic and magnetic properties of silver-doped single-walled ZnO nanotubes (SW-ZnO:AgNTs) with (6,0) chirality were investigated using density functional theory (DFT). The structural model was constructed by substituting one Zn atom with an Ag atom in a (6,0) ZnO nanotube containing 12 Zn and 12 O atoms. For single substitution, one Zn atom was replaced by one Ag atom, corresponding to <em>x</em> ≈ 0.08 in Ag<sub><em>x</em></sub>Zn<sub>1-<em>x</em></sub>O. For double substitution, two Zn atoms were replaced by Ag atoms (<em>x</em> ≈ 0.16), placed at non-adjacent Zn sites to reduce artificial interaction. In the double substitution configuration, Ag atoms were positioned at a minimum distance of ∼6.38 <em>Å</em> to study the effect of non-interacting dopants on the electronic and magnetic properties. All structures were fully relaxed using a force convergence criterion of 0.01 eV/Å. Spin-polarized DFT calculations were performed for all configurations to capture the magnetic response induced by Ag doping. Our simulations, performed using the Quantum ATK software, reveal that Ag doping induces notable changes in the electronic structure, including a reduction of the band gap and the emergence of spin polarization.</div><div>For pristine SW-ZnONTs, we obtain a direct band gap of 3.10 eV, confirming their semiconducting and non-magnetic nature. Ag doping breaks this symmetry and introduces strong spin polarization. In the singly doped system, the spin-up channel retains a reduced band gap of about 2.5 eV, while the spin-down channel becomes almost gapless at the Fermi level, indicating clear half-metallic behavior. Double Ag doping preserves this asymmetry and further enhances spin polarization, with a slightly smaller spin-up band gap than in the singly doped case. Mulliken analysis reveals a total magnetic moment of approximately 1.0 <em>μ</em><sub><em>B</em></sub> for single doping, originating mainly from the oxygen atoms (∼0.8 <em>μ</em><sub><em>B</em></sub>) surrounding the Ag dopant and a smaller contribution from Ag itself (∼0.2 <em>μ</em><sub><em>B</em></sub>). Total energy calculations comparing ferromagnetic and antiferromagnetic configurations show that the FM phase is energetically more favorable by 0.048 eV, confirming the stability of ferromagnetism in the doped nanotube. Quantitative analysis of the bound magnetic polaron (BMP) characteristics reveals effective BMP radii of ∼2.2 <em>Å</em> and a significant increase in BMP number density from single to double Ag doping, confirming a percolative BMP-mediated mechanism that stabilizes long-range ferromagnetism above room temperature. The estimated Curie temperature (≈370 <em>K</em>) confirms that the singly Ag-doped SW-ZnONT maintains stable ferromagnetic ordering above room temperature, highlighting its potential for spintronic devices. The structural integrity is preserved post-doping, with minimal atomic distortion, low residual forces, and negligible stress values,","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"408 ","pages":"Article 116261"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621822","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}
Pub Date : 2026-02-01Epub Date: 2025-12-31DOI: 10.1016/j.ssc.2025.116308
Jyotsana Negi , N.S. Panwar
The ceramic system Na1−xKxNbO3 (0.250 ≤ x ≤ 0.350) is prepared using the solid-state reaction method, and its phase structure and electrical properties are investigated as functions of temperature. Dielectric measurements are conducted from room temperature (RT) to 500 °C at 1 MHz, revealing three distinct phase transitions near 200 °C, 380 °C, and 460 °C for x values ranging from 0.250 to 0.350. Temperature-dependent X-ray powder diffraction of Na0.685K0.315NbO3 is performed, and the lattice parameters are determined using Rietveld refinement. The results revealed three distinct anomalies associated with successive M–T–T–C (monoclinic → two tetragonal → cubic) phase transitions. The transition temperatures shift slightly with increasing potassium content, indicating compositional control of phase stability. The high-temperature X-ray diffraction (HT-XRD) results are consistent with the observed dielectric properties, highlighting the structural transitions in Na1−xKxNbO3 ceramics.
{"title":"Electrical behavior of Na1-xKxNbO3 ceramics (0.25 ≤ x ≤ 0.35) and high-temperature phase transitions","authors":"Jyotsana Negi , N.S. Panwar","doi":"10.1016/j.ssc.2025.116308","DOIUrl":"10.1016/j.ssc.2025.116308","url":null,"abstract":"<div><div>The ceramic system Na<sub>1−x</sub>K<sub>x</sub>NbO<sub>3</sub> (0.250 ≤ x ≤ 0.350) is prepared using the solid-state reaction method, and its phase structure and electrical properties are investigated as functions of temperature. Dielectric measurements are conducted from room temperature (RT) to 500 °C at 1 MHz, revealing three distinct phase transitions near 200 °C, 380 °C, and 460 °C for x values ranging from 0.250 to 0.350. Temperature-dependent X-ray powder diffraction of Na<sub>0.685</sub>K<sub>0.315</sub>NbO<sub>3</sub> is performed, and the lattice parameters are determined using Rietveld refinement. The results revealed three distinct anomalies associated with successive M–T–T–C (monoclinic → two tetragonal → cubic) phase transitions. The transition temperatures shift slightly with increasing potassium content, indicating compositional control of phase stability. The high-temperature X-ray diffraction (HT-XRD) results are consistent with the observed dielectric properties, highlighting the structural transitions in Na<sub>1−x</sub>K<sub>x</sub>NbO<sub>3</sub> ceramics.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116308"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921197","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}
Pub Date : 2026-02-01Epub Date: 2025-12-23DOI: 10.1016/j.ssc.2025.116294
H.-M. Yang, G.-B. Zhu
In this paper, we present a study of longitudinal charge and spin current of two-dimensional electronic system with a quadratic band crossing point under irradiating of the linearly polarized light. The linearly polarized light can induce a pair of additional points in the system, where the energy splitting between the two energy branches vanishes. The locations of the points are determined by the amplitude of the light. Furthermore, the longitudinal charge and spin current can be controlled by tuning the amplitude of light field. The light field leads to the longitudinal spin current along the direction of electric field. Our work provides a way for manipulating transport properties in two dimensional materials that could facilitate the experimental detection and realistic applications.
{"title":"Longitudinal charge and spin current in two-dimensional electronic quadratic band system under the irradiating of linearly polarized light","authors":"H.-M. Yang, G.-B. Zhu","doi":"10.1016/j.ssc.2025.116294","DOIUrl":"10.1016/j.ssc.2025.116294","url":null,"abstract":"<div><div>In this paper, we present a study of longitudinal charge and spin current of two-dimensional electronic system with a quadratic band crossing point under irradiating of the linearly polarized light. The linearly polarized light can induce a pair of additional points in the system, where the energy splitting between the two energy branches vanishes. The locations of the points are determined by the amplitude of the light. Furthermore, the longitudinal charge and spin current can be controlled by tuning the amplitude of light field. The light field leads to the longitudinal spin current along the direction of electric field. Our work provides a way for manipulating transport properties in two dimensional materials that could facilitate the experimental detection and realistic applications.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116294"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837323","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}
Pub Date : 2026-02-01Epub Date: 2026-01-10DOI: 10.1016/j.ssc.2026.116324
A. Dydniański , M. Raczyński , A. Łopion , T. Kazimierczuk , J. Kasprzak , K.E. Połczyńska , W. Pacuski , P. Kossacki
In this work we look into how the contact material influences the local charge properties of a p-type CdTe-based quantum well. We study five metals deposited as 10 nm layers on the sample surface: Au, Ag, Cr, Ni and Ti. We use magneto-spectroscopy to discriminate their charge states through monitoring the Zeeman shifts at singlet-triplet transitions. Most tested metals retain the original p-type of the quantum well, while gold and nickel coverage flips the local doping to n-type. This is attributed to a robust bonding of these two metals to the semiconductor, efficiently passivating its surface and thus improving electron diffusion from the metal to the quantum well.
{"title":"Hole to electron crossover in a (Cd,Mn)Te quantum well through surface metallization","authors":"A. Dydniański , M. Raczyński , A. Łopion , T. Kazimierczuk , J. Kasprzak , K.E. Połczyńska , W. Pacuski , P. Kossacki","doi":"10.1016/j.ssc.2026.116324","DOIUrl":"10.1016/j.ssc.2026.116324","url":null,"abstract":"<div><div>In this work we look into how the contact material influences the local charge properties of a p-type CdTe-based quantum well. We study five metals deposited as 10 nm layers on the sample surface: Au, Ag, Cr, Ni and Ti. We use magneto-spectroscopy to discriminate their charge states through monitoring the Zeeman shifts at singlet-triplet transitions. Most tested metals retain the original p-type of the quantum well, while gold and nickel coverage flips the local doping to n-type. This is attributed to a robust bonding of these two metals to the semiconductor, efficiently passivating its surface and thus improving electron diffusion from the metal to the quantum well.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116324"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972812","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}
Pub Date : 2026-02-01Epub Date: 2025-11-26DOI: 10.1016/j.ssc.2025.116264
Yury M. Basalaev , Ekaterina B. Duginova , Sofia A. Marinova
Using density functional theory (DFT) methods, we modeled the chalcopyrite crystal structure of five hypothetical LiMS2 crystals (M = B, Al, Ga, In, Tl). Equilibrium lattice parameters were determined, stability conditions were investigated, and elastic stiffness constants along with fundamental elastic moduli were calculated. Three-dimensional isosurfaces of Young's modulus and compressibility were constructed. Cauchy pressures, microhardness, Grüneisen parameter, Poisson's ratio, fracture toughness, and brittleness index were computed. Phonon and infrared (IR) spectra were obtained, and atomic contributions to vibrational modes of the studied crystals were analyzed. The comprehensive set of theoretical results indicates the feasibility of synthesizing and the stability of tetragonal LiMS2 crystals with the chalcopyrite lattice structure.
利用密度泛函理论（DFT）方法，模拟了五种假设的LiMS2晶体（M = B, Al, Ga, In, Tl）的黄铜矿晶体结构。确定了平衡晶格参数，研究了稳定条件，计算了弹性刚度常数和基本弹性模量。构造了杨氏模量和压缩率的三维等值面。计算了柯西压力、显微硬度、颗粒尼森参数、泊松比、断裂韧性和脆性指数。获得了声子和红外光谱，并分析了原子对所研究晶体振动模式的贡献。综合理论结果表明，合成具有黄铜矿晶格结构的四边形LiMS2晶体是可行的，且具有稳定性。
{"title":"First-principles study of properties of hypothetical chalcopyrite-structured disulfides","authors":"Yury M. Basalaev , Ekaterina B. Duginova , Sofia A. Marinova","doi":"10.1016/j.ssc.2025.116264","DOIUrl":"10.1016/j.ssc.2025.116264","url":null,"abstract":"<div><div>Using density functional theory (DFT) methods, we modeled the chalcopyrite crystal structure of five hypothetical Li<em>M</em>S<sub>2</sub> crystals (<em>M</em> = B, Al, Ga, In, Tl). Equilibrium lattice parameters were determined, stability conditions were investigated, and elastic stiffness constants along with fundamental elastic moduli were calculated. Three-dimensional isosurfaces of Young's modulus and compressibility were constructed. Cauchy pressures, microhardness, Grüneisen parameter, Poisson's ratio, fracture toughness, and brittleness index were computed. Phonon and infrared (IR) spectra were obtained, and atomic contributions to vibrational modes of the studied crystals were analyzed. The comprehensive set of theoretical results indicates the feasibility of synthesizing and the stability of tetragonal Li<em>M</em>S<sub>2</sub> crystals with the chalcopyrite lattice structure.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116264"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623189","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}
Pub Date : 2026-02-01Epub Date: 2025-12-05DOI: 10.1016/j.ssc.2025.116276
Mustafa Bohra, Mikhail Zubkov
We investigate the interplay of chiral anomaly and dissipation in one-dimensional Dirac semimetal. For definiteness we consider the Su–Schrieffer–Heeger (SSH) model, which on the language of lattice field theory represents 1 D Wilson fermions. We employ the non-equilibrium Keldysh Green function formalism, and calculate the chiral imbalance and electric conductivity in the presence of energy dissipation, revealing how these observables are connected to the chiral anomaly. By systematically incorporating dissipation effects into the Keldysh framework, we demonstrate how the anomaly-induced contributions manifest in both axial charge density and electric current.
{"title":"Relation between chiral anomaly and electric transport in 1D Dirac semimetal","authors":"Mustafa Bohra, Mikhail Zubkov","doi":"10.1016/j.ssc.2025.116276","DOIUrl":"10.1016/j.ssc.2025.116276","url":null,"abstract":"<div><div>We investigate the interplay of chiral anomaly and dissipation in one-dimensional Dirac semimetal. For definiteness we consider the Su–Schrieffer–Heeger (SSH) model, which on the language of lattice field theory represents 1 D Wilson fermions. We employ the non-equilibrium Keldysh Green function formalism, and calculate the chiral imbalance and electric conductivity in the presence of energy dissipation, revealing how these observables are connected to the chiral anomaly. By systematically incorporating dissipation effects into the Keldysh framework, we demonstrate how the anomaly-induced contributions manifest in both axial charge density and electric current.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116276"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748817","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}
Pub Date : 2026-02-01Epub Date: 2025-12-09DOI: 10.1016/j.ssc.2025.116278
Yipeng Xiao , Qiubo Hu , Yudi Fan , Yuke Meng , Bingxu Huo , Shuang Liu , Wenbo Luo , Fengzi Zhou , Hao Li , Zhiyu Min , Xiaofei Wang
In this study, 82NaNbO3-18CaTiO3-xwt%MnO2 lead-free ceramics were prepared using the traditional solid-state method. The effects of different MnO2 doping levels (x = 0, 1, 2, 3) on the phase structure, microstructure, and dielectric properties of the materials were systematically investigated. The XRD analysis indicated that all samples displayed a stable perovskite structure and no secondary phase was detected, and Rietveld refinement analysis showed good fits for all samples, with GoF less than 2. As the amount of MnO2 doping increases, the diffraction peak shifts towards a smaller angle, suggesting that Mn2+/Mn3+ substitutes for B-site ions, resulting in lattice expansion. The SEM results indicate that doping with MnO2 significantly inhibits grain growth, and the average grain size decreases to 3.3 μm at x = 3, which is attributed to excessive MnO2 hindering grain boundary migration at grain boundaries. The dielectric properties tests indicate that εr and tanδ can be tuned by doping with MnO2, and the sample with x = 1 exhibits excellent temperature stability. In order to further analyze the dielectric properties of the samples, the electrical modulus (M") results showed a relaxation phenomenon, and the activation energy (Ea) was calculated by Arrhenius relationship. It was found that the change in the Ea value may be closely related to the OVs compensation mechanism. The existence of OVs was further confirmed by XPS analysis and its relationship with the MnO2 doping content was explained. Impedance measurements indicate that doping with MnO2 significantly improves the insulation performance of the material. The Ea was calculated, and the reasons for its variation were discussed. This study provides an experimental reference for the optimization of dielectric properties and defect regulation of lead-free antiferroelectric ceramic materials.
{"title":"The effects of MnO2 doping on the structure, dielectric properties and oxygen vacancies of 82NaNbO3-18CaTiO3 lead-free ceramics","authors":"Yipeng Xiao , Qiubo Hu , Yudi Fan , Yuke Meng , Bingxu Huo , Shuang Liu , Wenbo Luo , Fengzi Zhou , Hao Li , Zhiyu Min , Xiaofei Wang","doi":"10.1016/j.ssc.2025.116278","DOIUrl":"10.1016/j.ssc.2025.116278","url":null,"abstract":"<div><div>In this study, 82NaNbO<sub>3</sub>-18CaTiO<sub>3</sub>-xwt%MnO<sub>2</sub> lead-free ceramics were prepared using the traditional solid-state method. The effects of different MnO<sub>2</sub> doping levels (x = 0, 1, 2, 3) on the phase structure, microstructure, and dielectric properties of the materials were systematically investigated. The XRD analysis indicated that all samples displayed a stable perovskite structure and no secondary phase was detected, and Rietveld refinement analysis showed good fits for all samples, with GoF less than 2. As the amount of MnO<sub>2</sub> doping increases, the diffraction peak shifts towards a smaller angle, suggesting that Mn<sup>2+</sup>/Mn<sup>3+</sup> substitutes for B-site ions, resulting in lattice expansion. The SEM results indicate that doping with MnO<sub>2</sub> significantly inhibits grain growth, and the average grain size decreases to 3.3 μm at x = 3, which is attributed to excessive MnO<sub>2</sub> hindering grain boundary migration at grain boundaries. The dielectric properties tests indicate that ε<sub>r</sub> and tanδ can be tuned by doping with MnO<sub>2</sub>, and the sample with x = 1 exhibits excellent temperature stability. In order to further analyze the dielectric properties of the samples, the electrical modulus (M\") results showed a relaxation phenomenon, and the activation energy (E<sub>a</sub>) was calculated by Arrhenius relationship. It was found that the change in the E<sub>a</sub> value may be closely related to the OVs compensation mechanism. The existence of OVs was further confirmed by XPS analysis and its relationship with the MnO<sub>2</sub> doping content was explained. Impedance measurements indicate that doping with MnO<sub>2</sub> significantly improves the insulation performance of the material. The E<sub>a</sub> was calculated, and the reasons for its variation were discussed. This study provides an experimental reference for the optimization of dielectric properties and defect regulation of lead-free antiferroelectric ceramic materials.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116278"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748818","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}
In this work, we fabricated the single-phased DyAgGe intermetallic compound and experimentally determined its crystal structure, magnetic phase transition (MPT) and magnetocaloric properties. Our studies indicated that the DyAgGe intermetallic compound crystallizes in a hexagonal ZrNiAl-type (space group of P-62m) structure and shows antiferromagnetic ordering below TN of 13.5 K. Moderate conventional cryogenic magnetocaloric effect (MCE) in DyAgGe intermetallic compound together with inverse MCE have been observed which are attributed to its unique field-aligned first-order type MPT from antiferromagnetic ground state to ferromagnetic-like state. The MCE parameters of maximum magnetic entropy change and relative cooling power/refrigerant capacity (magnetic field variation of 0–70 kOe) for DyAgGe intermetallic compound are deduced to be 7.26 J/kgK and 211.3/148.8 J/kg, respectively.
{"title":"Magnetic phase transition and magnetocaloric effects in antiferromagnetic DyAgGe intermetallic compound","authors":"Wenchang Zhang, Jiameng Xu, Zhaoxing Wang, Yikun Zhang","doi":"10.1016/j.ssc.2025.116289","DOIUrl":"10.1016/j.ssc.2025.116289","url":null,"abstract":"<div><div>In this work, we fabricated the single-phased DyAgGe intermetallic compound and experimentally determined its crystal structure, magnetic phase transition (MPT) and magnetocaloric properties. Our studies indicated that the DyAgGe intermetallic compound crystallizes in a hexagonal ZrNiAl-type (space group of <em>P-62m</em>) structure and shows antiferromagnetic ordering below <em>T</em><sub>N</sub> of 13.5 K. Moderate conventional cryogenic magnetocaloric effect (MCE) in DyAgGe intermetallic compound together with inverse MCE have been observed which are attributed to its unique field-aligned first-order type MPT from antiferromagnetic ground state to ferromagnetic-like state. The MCE parameters of maximum magnetic entropy change and relative cooling power/refrigerant capacity (magnetic field variation of 0–70 kOe) for DyAgGe intermetallic compound are deduced to be 7.26 J/kgK and 211.3/148.8 J/kg, respectively.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116289"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921161","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}
In this work, nickel-based spinel oxides with the general formula NiB2O4 (B = Co, Fe, and Al) were synthesized via a facile combustion method to explore the role of B-site cations in tuning their physical and photocatalytic behavior. The main properties and oxidation states of the samples were comprehensively examined using various characterization tools, including X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), UV–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). The structural study by XRD affirmed the formation of crystal spinel phases for NiCo2O4, NiFe2O4 and NiAl2O4 with a mean crystallite size between 22 and 44 nm. Morphological SEM images well defined the spherical and nanosized grain crystals for all the samples. BET analysis further indicated that NiFe2O4 possesses a high specific surface area of 78 m2 g−1 and a pore width of 11.5 nm. The optical results showed that the obtained samples have an energy bandgap (Eg) value of 2.25, 1.73, and 2.24 eV for NiCo2O4, NiFe2O4, and NiAl2O4, respectively. The synthesized spinel oxides were evaluated as photocatalysts under UV light for the degradation of methylene blue dye (MB) and 4-nitrophenol(4-NP). The photodegradation results show that NiFe2O4 spinel exhibits the high rates with an efficiency of 86.65 % for MB within 80 min and a conversion rate of 70 % for 4-NP in only 15 min.
{"title":"Comparative study of NiB2O4 (B = Co, Fe, and Al) spinel nanoparticles: Structural, morphological, optical, and photocatalytic properties","authors":"Soumaia Khaldi , Abdelfattah Allaoui , Louiza Zenkhri , Safa Besra , Ece Tugba Saka , Cagla Akkol , Hakim Belkhalfa","doi":"10.1016/j.ssc.2025.116307","DOIUrl":"10.1016/j.ssc.2025.116307","url":null,"abstract":"<div><div>In this work, nickel-based spinel oxides with the general formula NiB<sub>2</sub>O<sub>4</sub> (B = Co, Fe, and Al) were synthesized via a facile combustion method to explore the role of B-site cations in tuning their physical and photocatalytic behavior. The main properties and oxidation states of the samples were comprehensively examined using various characterization tools, including X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), UV–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). The structural study by XRD affirmed the formation of crystal spinel phases for NiCo<sub>2</sub>O<sub>4</sub>, NiFe<sub>2</sub>O<sub>4</sub> and NiAl<sub>2</sub>O<sub>4</sub> with a mean crystallite size between 22 and 44 nm. Morphological SEM images well defined the spherical and nanosized grain crystals for all the samples. BET analysis further indicated that NiFe<sub>2</sub>O<sub>4</sub> possesses a high specific surface area of 78 m<sup>2</sup> g<sup>−1</sup> and a pore width of 11.5 nm. The optical results showed that the obtained samples have an energy bandgap (Eg) value of 2.25, 1.73, and 2.24 eV for NiCo<sub>2</sub>O<sub>4</sub>, NiFe<sub>2</sub>O<sub>4</sub>, and NiAl<sub>2</sub>O<sub>4</sub>, respectively. The synthesized spinel oxides were evaluated as photocatalysts under UV light for the degradation of methylene blue dye (MB) and 4-nitrophenol(4-NP). The photodegradation results show that NiFe<sub>2</sub>O<sub>4</sub> spinel exhibits the high rates with an efficiency of 86.65 % for MB within 80 min and a conversion rate of 70 % for 4-NP in only 15 min.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"409 ","pages":"Article 116307"},"PeriodicalIF":2.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921122","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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