We report a single-crystal study on the magnetism of the Sm honeycomb compound SmPt6Al3 with the trigonal NdPt6Al3-type structure by the measurements of the magnetic susceptibility χ, electrical resistivity, specific heat, and resonant X-ray diffraction. The trivalent state of the Sm ion is indicated by the fact that the lattice parameters fall on the lanthanoid contraction lines for the R3+Pt6Al3 series. For (Bparallel c), χ(T) shows a cusp at TN = 6.5 K and strongly decreases on cooling below TN, whereas χ(T) for (B perp c) continues to increase without showing any anomaly at TN. Application of (Bparallel c) = 12 T depresses TN to 4.6 K, whereas TN remains at 6.4 K in (B perp c) = 14 T. The isothermal magnetization curves at 1.8 K for both (Bparallel c) and (B perp c) have no spontaneous moment. These magnetic properties of SmPt6Al3 indicate a collinear antiferromagnetic structure of the ordered moments pointing toward the c axis. This magnetic structure is verified by the Sm resonant X-ray diffraction measurement which revealed the ([0,0,0]) propagation vector. By comparing the magnetic properties of SmPt6Al3 with those for the canted antiferromagnet GdPt6Al3, we highlight the role of Dzyaloshinskii–Moriya interaction in the series of isostructural compounds with the centrosymmetric NdPt6Al3-type structure.
我们报告了通过测量磁感应强度χ、电阻率、比热和共振 X 射线衍射，对具有三棱 NdPt6Al3 型结构的 Sm 蜂窝化合物 SmPt6Al3 的磁性进行的单晶研究。晶格参数落在 R3+Pt6Al3 系列的镧系收缩线上这一事实表明了 Sm 离子的三价态。对于(Bparallel c), χ(T)在TN = 6.5 K时显示出一个尖点，并且在低于TN时随着冷却而强烈减小，而对于(Bperp c), χ(T)继续增大，在TN处没有显示出任何异常。应用 (Bparallel c) = 12 T 时，TN 下降到 4.6 K，而 (Bperp c) = 14 T 时，TN 保持在 6.4 K。SmPt6Al3 的这些磁性能表明，有序磁矩指向 c 轴的共线反铁磁结构。这种磁性结构通过 Sm 共振 X 射线衍射测量得到了验证，测量结果显示了 ([0,0,0]) 传播矢量。通过将 SmPt6Al3 的磁性能与有尖角反铁磁体 GdPt6Al3 的磁性能进行比较，我们强调了 Dzyaloshinskii-Moriya 相互作用在具有中心对称 NdPt6Al3 型结构的等结构化合物系列中的作用。
{"title":"Collinear Antiferromagnet SmPt6Al3 with a Sm Honeycomb Structure Centered by Pt Triangles","authors":"Ryohei Oishi, Yasuyuki Shimura, Kazunori Umeo, Takahiro Onimaru, Takeshi Matsumura, Mitsuru Tsukagoshi, Kenshin Kurauchi, Hiroto Nitta, Toshiro Takabatake","doi":"10.7566/jpsj.93.034707","DOIUrl":"https://doi.org/10.7566/jpsj.93.034707","url":null,"abstract":"We report a single-crystal study on the magnetism of the Sm honeycomb compound SmPt<sub>6</sub>Al<sub>3</sub> with the trigonal NdPt<sub>6</sub>Al<sub>3</sub>-type structure by the measurements of the magnetic susceptibility <i>χ</i>, electrical resistivity, specific heat, and resonant X-ray diffraction. The trivalent state of the Sm ion is indicated by the fact that the lattice parameters fall on the lanthanoid contraction lines for the <i>R</i><sup>3+</sup>Pt<sub>6</sub>Al<sub>3</sub> series. For <tex-math space=\"preserve\" version=\"MathJax\">(Bparallel c)</tex-math>, <i>χ</i>(<i>T</i>) shows a cusp at <i>T</i><sub>N</sub> = 6.5 K and strongly decreases on cooling below <i>T</i><sub>N</sub>, whereas <i>χ</i>(<i>T</i>) for <tex-math space=\"preserve\" version=\"MathJax\">(B perp c)</tex-math> continues to increase without showing any anomaly at <i>T</i><sub>N</sub>. Application of <tex-math space=\"preserve\" version=\"MathJax\">(Bparallel c)</tex-math> = 12 T depresses <i>T</i><sub>N</sub> to 4.6 K, whereas <i>T</i><sub>N</sub> remains at 6.4 K in <tex-math space=\"preserve\" version=\"MathJax\">(B perp c)</tex-math> = 14 T. The isothermal magnetization curves at 1.8 K for both <tex-math space=\"preserve\" version=\"MathJax\">(Bparallel c)</tex-math> and <tex-math space=\"preserve\" version=\"MathJax\">(B perp c)</tex-math> have no spontaneous moment. These magnetic properties of SmPt<sub>6</sub>Al<sub>3</sub> indicate a collinear antiferromagnetic structure of the ordered moments pointing toward the <i>c</i> axis. This magnetic structure is verified by the Sm resonant X-ray diffraction measurement which revealed the <tex-math space=\"preserve\" version=\"MathJax\">([0,0,0])</tex-math> propagation vector. By comparing the magnetic properties of SmPt<sub>6</sub>Al<sub>3</sub> with those for the canted antiferromagnet GdPt<sub>6</sub>Al<sub>3</sub>, we highlight the role of Dzyaloshinskii–Moriya interaction in the series of isostructural compounds with the centrosymmetric NdPt<sub>6</sub>Al<sub>3</sub>-type structure.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"16 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139977645","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 order to study the mechanism of submicron-scale air gap discharge, the gas discharge experiment with electrode gap of 0.3–10 um was carried out by using nano-positioning system under atmospheric pressure. The breakdown voltages of stainless steel, brass, copper, and aluminum electrodes were measured. The experimental results are obviously deviated from the Paschen curve, and the Paschen curve cannot explain the air gap breakdown voltage. It is found that in the range of 0.3–5 um, the material work function significantly affects the air gap breakdown voltage, and it is not obvious in the range of 5–10 um. By studying the breakdown field strength, current density and F–N theory, it is found that when the electrode gap is 0.3–5 um, the field emission is dominant, resulting in the breakdown voltage deviating from the Paschen curve. In addition, the breakdown voltages under different discharge mechanisms are numerically calculated, and the numerical results are compared with the experimental results. The results show that only field emission needs to be considered at the gap of 0.3–2 um, and other discharge mechanisms can be ignored. Through the research of this paper, it provides a basis for the in-depth study of sub-micron electrical breakdown and the design of microelectronic devices.
为了研究亚微米尺度气隙放电的机理，利用纳米定位系统在大气压力下进行了电极间隙为 0.3-10 um 的气体放电实验。测量了不锈钢、黄铜、铜和铝电极的击穿电压。实验结果明显偏离帕申曲线，帕申曲线无法解释气隙击穿电压。实验发现，在 0.3-5 um 范围内，材料功函数对气隙击穿电压的影响明显，而在 5-10 um 范围内影响不明显。通过研究击穿场强、电流密度和 F-N 理论，发现当电极间隙为 0.3-5 um 时，场发射占主导地位，导致击穿电压偏离帕申曲线。此外，还对不同放电机制下的击穿电压进行了数值计算，并将数值结果与实验结果进行了比较。结果表明，在间隙为 0.3-2 um 时只需考虑场发射，其他放电机制可以忽略。通过本文的研究，为深入研究亚微米电击穿和微电子器件的设计提供了依据。
{"title":"Experimental Study and Analysis of Sub-Micron Scale Air Gap Breakdown","authors":"Guoda Wang, Yanzhou Sun, Hao Zhang, Guokai Ma, Laijun Zhao","doi":"10.7566/jpsj.93.034502","DOIUrl":"https://doi.org/10.7566/jpsj.93.034502","url":null,"abstract":"In order to study the mechanism of submicron-scale air gap discharge, the gas discharge experiment with electrode gap of 0.3–10 um was carried out by using nano-positioning system under atmospheric pressure. The breakdown voltages of stainless steel, brass, copper, and aluminum electrodes were measured. The experimental results are obviously deviated from the Paschen curve, and the Paschen curve cannot explain the air gap breakdown voltage. It is found that in the range of 0.3–5 um, the material work function significantly affects the air gap breakdown voltage, and it is not obvious in the range of 5–10 um. By studying the breakdown field strength, current density and F–N theory, it is found that when the electrode gap is 0.3–5 um, the field emission is dominant, resulting in the breakdown voltage deviating from the Paschen curve. In addition, the breakdown voltages under different discharge mechanisms are numerically calculated, and the numerical results are compared with the experimental results. The results show that only field emission needs to be considered at the gap of 0.3–2 um, and other discharge mechanisms can be ignored. Through the research of this paper, it provides a basis for the in-depth study of sub-micron electrical breakdown and the design of microelectronic devices.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"20 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139977769","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}
Yudai Kawaue, Ryohei Oishi, Chongli Yang, Rikako Yamamoto, Yasuyuki Shimura, Kazunori Umeo, Takahiro Onimaru, Devashibhai T. Adroja, Helen C. Walker, Toshiro Takabatake
CePd3Sn2 with Ce-chains along the orthorhombic b axis has been reported to order antiferromagnetically at TN ∼ 0.6 K. Above TN, the specific heat C(T) exhibits a long tail whose origin remains elusive. Here we report on the physical properties of single-crystalline samples inferred from electrical resistivity ρ(T), magnetization M(B), and C(T). The measurements reveal rather weak anisotropic properties characterized by the lowest ρ(T) and the highest saturation M(B) along the b axis. The ρ(T) data along the three principal directions exhibit no clear signature of Kondo scattering and decrease with negative curvatures on cooling from 2 K to TN = 0.67 K. The magnetic susceptibility and inelastic neutron scattering data are reproduced by the crystal electric field (CEF) model for the Ce3+ ion with two excited CEF doublets at rather low energies 27 and 191 K, respectively, above the ground state doublet. The isothermal M(B) curves at 0.3 K show metamagnetic transitions at B || b = 1.8 T and B || c = 1.5 T and upward increases before saturation for the three directions. The antiferromagnetic order is destroyed by the application of magnetic field in an anisotropic way at around B || b = 3 T, B || c = 4 T, and B || a = 5 T. The obtained results are discussed by comparing with those reported for quasi-one-dimensional Ce compounds.
据报道，在 TN ∼ 0.6 K 时，沿正交 b 轴具有铈链的 CePd3Sn2 具有反铁磁有序性。在此，我们报告了从电阻率 ρ(T)、磁化 M(B) 和 C(T) 推断出的单晶样品的物理性质。测量结果揭示了相当弱的各向异性，其特点是沿 b 轴的 ρ(T) 最低，而饱和 M(B) 最高。沿三个主要方向的 ρ(T) 数据没有表现出明显的 Kondo 散射特征，并且在从 2 K 冷却到 TN = 0.67 K 时以负曲率下降。磁感应强度和非弹性中子散射数据由 Ce3+ 离子的晶体电场 (CEF) 模型再现，其两个激发的 CEF 双态能量分别为 27 K 和 191 K，高于基态双态能量。0.3 K 时的等温 M(B) 曲线显示了 B || b = 1.8 T 和 B || c = 1.5 T 时的元磁跃迁，以及三个方向饱和前的向上增长。在 B || b = 3 T、B || c = 4 T 和 B || a = 5 T 左右，各向异性磁场的应用破坏了反铁磁秩序。
{"title":"Weak Kondo Coupling Antiferromagnet CePd3Sn2 with Quasi-One-Dimensional Ce Chains","authors":"Yudai Kawaue, Ryohei Oishi, Chongli Yang, Rikako Yamamoto, Yasuyuki Shimura, Kazunori Umeo, Takahiro Onimaru, Devashibhai T. Adroja, Helen C. Walker, Toshiro Takabatake","doi":"10.7566/jpsj.93.034706","DOIUrl":"https://doi.org/10.7566/jpsj.93.034706","url":null,"abstract":"CePd<sub>3</sub>Sn<sub>2</sub> with Ce-chains along the orthorhombic <i>b</i> axis has been reported to order antiferromagnetically at <i>T</i><sub>N</sub> ∼ 0.6 K. Above <i>T</i><sub>N</sub>, the specific heat <i>C</i>(<i>T</i>) exhibits a long tail whose origin remains elusive. Here we report on the physical properties of single-crystalline samples inferred from electrical resistivity <i>ρ</i>(<i>T</i>), magnetization <i>M</i>(<i>B</i>), and <i>C</i>(<i>T</i>). The measurements reveal rather weak anisotropic properties characterized by the lowest <i>ρ</i>(<i>T</i>) and the highest saturation <i>M</i>(<i>B</i>) along the <i>b</i> axis. The <i>ρ</i>(<i>T</i>) data along the three principal directions exhibit no clear signature of Kondo scattering and decrease with negative curvatures on cooling from 2 K to <i>T</i><sub>N</sub> = 0.67 K. The magnetic susceptibility and inelastic neutron scattering data are reproduced by the crystal electric field (CEF) model for the Ce<sup>3+</sup> ion with two excited CEF doublets at rather low energies 27 and 191 K, respectively, above the ground state doublet. The isothermal <i>M</i>(<i>B</i>) curves at 0.3 K show metamagnetic transitions at <i>B</i> || <i>b</i> = 1.8 T and <i>B</i> || <i>c</i> = 1.5 T and upward increases before saturation for the three directions. The antiferromagnetic order is destroyed by the application of magnetic field in an anisotropic way at around <i>B</i> || <i>b</i> = 3 T, <i>B</i> || <i>c</i> = 4 T, and <i>B</i> || <i>a</i> = 5 T. The obtained results are discussed by comparing with those reported for quasi-one-dimensional Ce compounds.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"34 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139981634","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}
Rei Nishimura, Shun Katakami, Kenji Nagata, Masaichiro Mizumaki, Masato Okada
Multidimensional measurements and a cohesive interpretation of the obtained results are imperative for comprehending the underlying mechanisms of physical phenomena. In this dissertation, we propose the utilization of Bayesian integration as a method for obtaining a consolidated interpretation of results, based on Bayesian inference. We focus on 4f electron systems, which can be comprehended through the use of a relatively simple Hamiltonian. The measurements performed center on fundamental macroscopic properties: magnetic susceptibility and specific heat. We conduct simulations utilizing data obtained from two distinct measurements, namely magnetic susceptibility and specific heat, and demonstrate that the implementation of Bayesian integration enhances precision.
{"title":"Bayesian Integration for Hamiltonian Parameters of Crystal Field","authors":"Rei Nishimura, Shun Katakami, Kenji Nagata, Masaichiro Mizumaki, Masato Okada","doi":"10.7566/jpsj.93.034003","DOIUrl":"https://doi.org/10.7566/jpsj.93.034003","url":null,"abstract":"Multidimensional measurements and a cohesive interpretation of the obtained results are imperative for comprehending the underlying mechanisms of physical phenomena. In this dissertation, we propose the utilization of Bayesian integration as a method for obtaining a consolidated interpretation of results, based on Bayesian inference. We focus on 4<i>f</i> electron systems, which can be comprehended through the use of a relatively simple Hamiltonian. The measurements performed center on fundamental macroscopic properties: magnetic susceptibility and specific heat. We conduct simulations utilizing data obtained from two distinct measurements, namely magnetic susceptibility and specific heat, and demonstrate that the implementation of Bayesian integration enhances precision.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"20 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139926410","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}
A feasibility study was conducted on thin film surface analysis using conversion electron Mössbauer spectroscopy (CEMS) measured at incident angles more than the critical angle and less than several degrees, utilizing a synchrotron Mössbauer source. To identify the minimum incident angle yielding a CEMS spectrum with experimentally negligible nuclear specular reflection effects, γ-ray reflection and CEMS of a 57Fe [90%] enriched thin film were studied by grazing-incidence synchrotron Mössbauer spectroscopy, varying the incident angle in the range of 0.3 to 3°. Since the incident angles were larger than the critical angle (θc ∼ 0.22°) of the iron film for 14.4 keV X-rays, the photons passing through the nuclear resonant channel, rather than the electronic non-resonant channel, predominantly contributed to the specular reflection. Consequently, at θin = 0.3°, strong scattering peaks appeared at nuclear resonance energies, and then CEMS showed an anomalous spectral profile. At θin > θc, the nuclear specular reflection gradually decreased with increasing θin, whereas nuclear resonance peaks were persistently observed up to θin = 1.5°. Finally, the reflection signals were nearly extinguished at around θin = 3°, and the CEMS showed an experimentally normal spectral profile in usual use. Low-angle incidence CEMS with negligible nuclear specular reflection is advantageous for surface analysis of thin films because the penetration depth of γ-rays is still shorter than the conversion electron escape depth. Furthermore, a surface analysis of an annealed 57Fe-rich film was conducted using low-angle incidence CEMS with circularly polarized synchrotron Mössbauer source. The present paper also describes the theoretical background and additional benefits in instrument development.
{"title":"Feasibility Study of Thin Film Surface Analysis Using Synchrotron Low-Angle Incidence Conversion Electron Mössbauer Spectroscopy","authors":"Takaya Mitsui, Kosuke Fujiwara, Ko Mibu, Ryo Masuda, Yasuhiro Kobayashi, Makoto Seto","doi":"10.7566/jpsj.93.034705","DOIUrl":"https://doi.org/10.7566/jpsj.93.034705","url":null,"abstract":"A feasibility study was conducted on thin film surface analysis using conversion electron Mössbauer spectroscopy (CEMS) measured at incident angles more than the critical angle and less than several degrees, utilizing a synchrotron Mössbauer source. To identify the minimum incident angle yielding a CEMS spectrum with experimentally negligible nuclear specular reflection effects, γ-ray reflection and CEMS of a <sup>57</sup>Fe [90%] enriched thin film were studied by grazing-incidence synchrotron Mössbauer spectroscopy, varying the incident angle in the range of 0.3 to 3°. Since the incident angles were larger than the critical angle (<i>θ</i><sub>c</sub> ∼ 0.22°) of the iron film for 14.4 keV X-rays, the photons passing through the nuclear resonant channel, rather than the electronic non-resonant channel, predominantly contributed to the specular reflection. Consequently, at <i>θ</i><sub>in</sub> = 0.3°, strong scattering peaks appeared at nuclear resonance energies, and then CEMS showed an anomalous spectral profile. At <i>θ</i><sub>in</sub> > <i>θ</i><sub>c</sub>, the nuclear specular reflection gradually decreased with increasing <i>θ</i><sub>in</sub>, whereas nuclear resonance peaks were persistently observed up to <i>θ</i><sub>in</sub> = 1.5°. Finally, the reflection signals were nearly extinguished at around <i>θ</i><sub>in</sub> = 3°, and the CEMS showed an experimentally normal spectral profile in usual use. Low-angle incidence CEMS with negligible nuclear specular reflection is advantageous for surface analysis of thin films because the penetration depth of γ-rays is still shorter than the conversion electron escape depth. Furthermore, a surface analysis of an annealed <sup>57</sup>Fe-rich film was conducted using low-angle incidence CEMS with circularly polarized synchrotron Mössbauer source. The present paper also describes the theoretical background and additional benefits in instrument development.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"34 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139926411","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}
New study is made for the impact of three different plasma potentials on the low-lying and core excited doublet states of the lithium atom using the variational Monte Carlo method. The considered low-lying excited doublet states include the states: 1s2ns, 1s2np, and 1s2nd, whereas the core excited states include the states: 1sn1l1n1l2 and 1sn1l1n2l2. Also, the three used plasma potentials are: screened Coulomb, exponential cosine screened Coulomb, and Hulthén potentials. The energy eigenvalues of the excited states are evaluated freely and under the influence of the plasma potentials using suitable trial wave functions including the spin and the correlated (electron–electron repulsion) parts. In addition, a suggested effective-plasma factor is considered in the wave function regarding the exponential cosine screened Coulomb potential model due to the dense plasma particle interactions. Interesting relative ordering of eigenvalues is reported for the excited states of the lithium atom corresponding to the three different screened Coulomb potentials.
{"title":"Low-Lying and Core Excited Doublet States of Lithium Atom in Various Plasma Environments","authors":"Salah Doma, Gamal Roston, Mostafa Ahmed","doi":"10.7566/jpsj.93.034301","DOIUrl":"https://doi.org/10.7566/jpsj.93.034301","url":null,"abstract":"New study is made for the impact of three different plasma potentials on the low-lying and core excited doublet states of the lithium atom using the variational Monte Carlo method. The considered low-lying excited doublet states include the states: 1<i>s</i><sup>2</sup><i>ns</i>, 1<i>s</i><sup>2</sup><i>np</i>, and 1<i>s</i><sup>2</sup><i>nd</i>, whereas the core excited states include the states: 1<i>s</i> <i>n</i><sub>1</sub><i>l</i><sub>1</sub><i>n</i><sub>1</sub><i>l</i><sub>2</sub> and 1<i>s</i> <i>n</i><sub>1</sub><i>l</i><sub>1</sub><i>n</i><sub>2</sub><i>l</i><sub>2</sub>. Also, the three used plasma potentials are: screened Coulomb, exponential cosine screened Coulomb, and Hulthén potentials. The energy eigenvalues of the excited states are evaluated freely and under the influence of the plasma potentials using suitable trial wave functions including the spin and the correlated (electron–electron repulsion) parts. In addition, a suggested effective-plasma factor is considered in the wave function regarding the exponential cosine screened Coulomb potential model due to the dense plasma particle interactions. Interesting relative ordering of eigenvalues is reported for the excited states of the lithium atom corresponding to the three different screened Coulomb potentials.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"300 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139902675","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}
An elliptical camphor-coated paper disk whose center of mass is fixed at the rotational axis rotates spontaneously with a constant angular velocity when placed on the surface of water. In our experiments, we observed bifurcation by controlling the water depth, i.e., the disk rotated and was stationary at higher and lower water depths, respectively. Further, the bifurcation type depended on the aspect ratio of the elliptical camphor disk; subcritical and supercritical bifurcations were observed in the high- and low-aspect-ratio experiments, respectively. Thus, the experiments and phenomenological models indicated that the friction between the acrylic rod as the rotational axis and the center pore of the disk penetrated by the rod determined the bifurcation type.
{"title":"Transition of the Bifurcations in the Rotation of a Camphor-Coated Elliptical Paper Disk","authors":"Michiko Shimokawa, Junma Arimitsu, Hiroyuki Kitahata, Hidetsugu Sakaguchi","doi":"10.7566/jpsj.93.034002","DOIUrl":"https://doi.org/10.7566/jpsj.93.034002","url":null,"abstract":"An elliptical camphor-coated paper disk whose center of mass is fixed at the rotational axis rotates spontaneously with a constant angular velocity when placed on the surface of water. In our experiments, we observed bifurcation by controlling the water depth, i.e., the disk rotated and was stationary at higher and lower water depths, respectively. Further, the bifurcation type depended on the aspect ratio of the elliptical camphor disk; subcritical and supercritical bifurcations were observed in the high- and low-aspect-ratio experiments, respectively. Thus, the experiments and phenomenological models indicated that the friction between the acrylic rod as the rotational axis and the center pore of the disk penetrated by the rod determined the bifurcation type.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"197 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751153","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}
Magnetism of layered compound Eu1−xCaxCo2P2 was investigated by means of magnetization, specific heat, and electrical resistivity measurements. It is found that Eu undergoes a phase transition from a divalent state to a mixed-valence state of Eu2+δ and Eu(3−δ′)+ simultaneously with a structural transition from the uncollapsed tetragonal (ucT) phase to the collapsed tetragonal (cT) phase near x = 0.5. Whereas the compounds with the ucT structure exhibit antiferromagnetic ordering of Eu2+ moments, those with the cT structure exhibit additional magnetic ordering of Co moments. The ordering temperature of Co moments is much higher than those in other ACo2P2 systems with a divalent A cation. These results suggest that an electron-doping effect on Co 3d bands owing to the Eu valence transition stabilizes the magnetic ordering of Co moments.
通过磁化、比热和电阻率测量，研究了层状化合物 Eu1-xCaxCo2P2 的磁性。研究发现，在 x = 0.5 附近，Eu 经历了从二价态到 Eu2+δ 和 Eu(3-δ′)+混合价态的相变，同时发生了从非塌缩四方（ucT）相到塌缩四方（cT）相的结构转变。具有 ucT 结构的化合物表现出 Eu2+ 矩的反铁磁排序，而具有 cT 结构的化合物则表现出 Co 矩的附加磁性排序。Co 矩的有序温度远高于其他含有二价 A 阳离子的 ACo2P2 系统。这些结果表明，Eu 价态转变对 Co 3d 带产生的电子掺杂效应稳定了 Co 矩的磁有序性。
{"title":"Magnetic Order Induced by the Cooperation of Valence and Structural Instabilities in Eu1−xCaxCo2P2","authors":"Kodai Moriyama, Kohei Yoshinaga, Ryoichiro Matsui, Chishiro Michioka, Hiroaki Ueda, Kazuyoshi Yoshimura","doi":"10.7566/jpsj.93.033702","DOIUrl":"https://doi.org/10.7566/jpsj.93.033702","url":null,"abstract":"Magnetism of layered compound Eu<sub>1−</sub><i><sub>x</sub></i>Ca<i><sub>x</sub></i>Co<sub>2</sub>P<sub>2</sub> was investigated by means of magnetization, specific heat, and electrical resistivity measurements. It is found that Eu undergoes a phase transition from a divalent state to a mixed-valence state of Eu<sup>2+</sup><i><sup>δ</sup></i> and Eu<sup>(3−</sup><i><sup>δ</sup></i><sup>′)+</sup> simultaneously with a structural transition from the uncollapsed tetragonal (ucT) phase to the collapsed tetragonal (cT) phase near <i>x</i> = 0.5. Whereas the compounds with the ucT structure exhibit antiferromagnetic ordering of Eu<sup>2+</sup> moments, those with the cT structure exhibit additional magnetic ordering of Co moments. The ordering temperature of Co moments is much higher than those in other <i>A</i>Co<sub>2</sub>P<sub>2</sub> systems with a divalent <i>A</i> cation. These results suggest that an electron-doping effect on Co 3<i>d</i> bands owing to the Eu valence transition stabilizes the magnetic ordering of Co moments.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"98 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751248","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}
Tomonari Meguro, Akihiro Ozawa, Koji Kobayashi, Kentaro Nomura
The effective tight-binding model with compensated ferrimagnetic inverse-Heusler lattice Ti2MnAl, candidate material of magnetic Weyl semimetal, is proposed. The energy spectrum near the Fermi level, the configurations of the Weyl points, and the anomalous Hall conductivity are calculated. We found that the orbital magnetization is finite, while the total spin magnetization vanishes, at the energy of the Weyl points. The magnetic moments at each site are correlated with the orbital magnetization and can be controlled by the external magnetic field.
{"title":"Effective Tight-Binding Model of Compensated Ferrimagnetic Weyl Semimetal with Spontaneous Orbital Magnetization","authors":"Tomonari Meguro, Akihiro Ozawa, Koji Kobayashi, Kentaro Nomura","doi":"10.7566/jpsj.93.034703","DOIUrl":"https://doi.org/10.7566/jpsj.93.034703","url":null,"abstract":"The effective tight-binding model with compensated ferrimagnetic inverse-Heusler lattice Ti<sub>2</sub>MnAl, candidate material of magnetic Weyl semimetal, is proposed. The energy spectrum near the Fermi level, the configurations of the Weyl points, and the anomalous Hall conductivity are calculated. We found that the orbital magnetization is finite, while the total spin magnetization vanishes, at the energy of the Weyl points. The magnetic moments at each site are correlated with the orbital magnetization and can be controlled by the external magnetic field.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"2 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751247","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 derive a quantum spin Hamiltonian of the spin-1/2 zigzag chain realized in a rare earth ytterbium-based magnetic insulator, YbCuS2. This material undergoes a transition at 0.95 K to an incommensurate magnetic phase with small moments, which does not conform to the prediction of nonmagnetic singlet ground state of the spin-1/2 Heisenberg model. We take account of octahedral crystal field effect, atomic spin–orbit coupling, and strong Coulomb interactions on Yb ions, and perform a fourth-order perturbation theory to evaluate the superexchange coupling constants. A small but finite anisotropic exchange coupling called Γ-term appears similarly to the case reported previously in other triangular-based magnets. By varying several material parameters, we figure out two important factors to enhance the Γ-term. One is the splitting of excited f-states with two holes, which efficiently selects the perturbation terms associated with the lowest excited state having large total angular momentum, and accordingly with high spatial anisotropy. The other is the tilting of octahedra or distortion of S–Yb–S bond angle, which breaks the symmetry of the Slater–Koster overlap. These effects are systematically analyzed by focusing on the anisotropy of exchange interactions between two spins using the local axis frame, which reduces the complexity of dealing with the bulk Hamiltonian described in a global axis frame.
我们推导了在稀土镱基磁性绝缘体 YbCuS2 中实现的自旋-1/2 之字链的量子自旋哈密顿。这种材料在 0.95 K 时过渡到具有小矩的不相称磁性相，这与自旋-1/2 海森堡模型的非磁性单基态预言不符。我们考虑了八面体晶体场效应、原子自旋轨道耦合以及镱离子上的强库仑相互作用，并采用四阶扰动理论来评估超交换耦合常数。与之前报道的其他基于三角形的磁体的情况类似，出现了一个很小但有限的称为Γ项的各向异性交换耦合。通过改变几个材料参数，我们找出了增强 Γ 项的两个重要因素。其一是激发 f 态与两个孔的分裂，这有效地选择了与具有大总角动量的最低激发态相关的扰动项，并相应地选择了具有高空间各向异性的扰动项。另一种情况是八面体倾斜或 S-Yb-S 键角扭曲，这打破了斯莱特-科斯特重叠的对称性。通过使用局部轴框架关注两个自旋之间交换相互作用的各向异性，我们系统地分析了这些效应，从而降低了处理全局轴框架描述的大体哈密顿的复杂性。
{"title":"Deriving Quantum Spin Model for a Zigzag-Chain Ytterbium Magnet with Anisotropic Exchange Interactions","authors":"Hidehiro Saito, Hiroki Nakai, Chisa Hotta","doi":"10.7566/jpsj.93.034701","DOIUrl":"https://doi.org/10.7566/jpsj.93.034701","url":null,"abstract":"We derive a quantum spin Hamiltonian of the spin-1/2 zigzag chain realized in a rare earth ytterbium-based magnetic insulator, YbCuS<sub>2</sub>. This material undergoes a transition at 0.95 K to an incommensurate magnetic phase with small moments, which does not conform to the prediction of nonmagnetic singlet ground state of the spin-1/2 Heisenberg model. We take account of octahedral crystal field effect, atomic spin–orbit coupling, and strong Coulomb interactions on Yb ions, and perform a fourth-order perturbation theory to evaluate the superexchange coupling constants. A small but finite anisotropic exchange coupling called Γ-term appears similarly to the case reported previously in other triangular-based magnets. By varying several material parameters, we figure out two important factors to enhance the Γ-term. One is the splitting of excited <i>f</i>-states with two holes, which efficiently selects the perturbation terms associated with the lowest excited state having large total angular momentum, and accordingly with high spatial anisotropy. The other is the tilting of octahedra or distortion of S–Yb–S bond angle, which breaks the symmetry of the Slater–Koster overlap. These effects are systematically analyzed by focusing on the anisotropy of exchange interactions between two spins using the local axis frame, which reduces the complexity of dealing with the bulk Hamiltonian described in a global axis frame.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139656667","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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