Pub Date : 2006-07-26DOI: 10.11429/SUGAKU1947.58.225
礼子 宮岡
{"title":"4つの主曲率をもつ等径超曲面のT. E. Cecil, Q. S. Chi, G. R. Jensenによる分類","authors":"礼子 宮岡","doi":"10.11429/SUGAKU1947.58.225","DOIUrl":"https://doi.org/10.11429/SUGAKU1947.58.225","url":null,"abstract":"","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124906815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Self-consistent APW band calculations are carried out for non-magnetic states of transition-metal intermetallic compounds having Cu 2 Sb-type crystal structure. The energy dispersions, densities of states and Fermi surfaces are shown. Differences and similarities of the electronic band structures of Cr, Mn, Fe-arsenides are clarified. To discuss the bonding nature, calculations of the bond order are also carried out.
{"title":"Electronic Band Structures of Cu 2 Sb-Type Intermetallic Compounds","authors":"T. Chonan, A. Yamada, K. Motizuki","doi":"10.1143/JPSJ.60.1638","DOIUrl":"https://doi.org/10.1143/JPSJ.60.1638","url":null,"abstract":"Self-consistent APW band calculations are carried out for non-magnetic states of transition-metal intermetallic compounds having Cu 2 Sb-type crystal structure. The energy dispersions, densities of states and Fermi surfaces are shown. Differences and similarities of the electronic band structures of Cr, Mn, Fe-arsenides are clarified. To discuss the bonding nature, calculations of the bond order are also carried out.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116385790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Itaru Maekawa, F. Takagi, K. Kaneda, Y. Sakai, N. Tsuda
Magnetic susceptibility of Li 1+ x Ti 2- x O 4 doped with V by 5% was measured from 90 to 300 K. It was analyzed as a sum of those of the host lattice and the resolved V. The susceptibility of V obeys the Curie-Weiss law. The effective Bohr magneton number is 2.4–2.8/V and the Weiss temperature is as low as 20 K. They suggest that the bipolaron state does not appear in the host lattice. To explain the nearly temperature independent paramagnetism of the host lattice, spin degeneracy of locally extended electron orbitals was proposed.
在90 ~ 300 K范围内测定了掺5% V的Li 1+ x Ti 2- x o4的磁化率。将其作为主晶格和解析V的和来分析，V的磁化率符合居里-魏斯定律。有效玻尔磁子数为2.4 ~ 2.8/V, Weiss温度低至20 K。他们认为双极化子态不会出现在主晶格中。为了解释宿主晶格几乎与温度无关的顺磁性，提出了局部扩展电子轨道的自旋简并。
{"title":"Magnetic Susceptibility of Li 1+ x Ti 2− x O 4 Doped with Vanadium","authors":"Itaru Maekawa, F. Takagi, K. Kaneda, Y. Sakai, N. Tsuda","doi":"10.1143/JPSJ.56.2853","DOIUrl":"https://doi.org/10.1143/JPSJ.56.2853","url":null,"abstract":"Magnetic susceptibility of Li 1+ x Ti 2- x O 4 doped with V by 5% was measured from 90 to 300 K. It was analyzed as a sum of those of the host lattice and the resolved V. The susceptibility of V obeys the Curie-Weiss law. The effective Bohr magneton number is 2.4–2.8/V and the Weiss temperature is as low as 20 K. They suggest that the bipolaron state does not appear in the host lattice. To explain the nearly temperature independent paramagnetism of the host lattice, spin degeneracy of locally extended electron orbitals was proposed.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114555562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phase diagrams of mixed crystals between a ferroelectric and an antiferroelectric crystals, both belonging to the KH 2 PO 4 -family, were discussed on the basis of the Slater model. The free energy function for the antiferroelectric transition was analyzed in some detail. The role of the intersublattice interaction, which is substantial for giving rise to the antiferroelectric transition, was reconsidered and it is pointed out that a ferroelectric phase with the polarization along the [110] direction may be stabilized when the interaction changes its sign. Also the role of the intrasublattice interaction is mentioned. The results are discussed in the relationship with the RbH 2 PO 4 –NH 4 H 2 PO 4 mixed crystal system.
{"title":"On Phase Diagrams of Mixed Crystals of the KH 2 PO 4 -Family","authors":"Y. Ishibashi, I. Suzuki","doi":"10.1143/JPSJ.54.1443","DOIUrl":"https://doi.org/10.1143/JPSJ.54.1443","url":null,"abstract":"Phase diagrams of mixed crystals between a ferroelectric and an antiferroelectric crystals, both belonging to the KH 2 PO 4 -family, were discussed on the basis of the Slater model. The free energy function for the antiferroelectric transition was analyzed in some detail. The role of the intersublattice interaction, which is substantial for giving rise to the antiferroelectric transition, was reconsidered and it is pointed out that a ferroelectric phase with the polarization along the [110] direction may be stabilized when the interaction changes its sign. Also the role of the intrasublattice interaction is mentioned. The results are discussed in the relationship with the RbH 2 PO 4 –NH 4 H 2 PO 4 mixed crystal system.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133083340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dielectric, pyroelectric and thermal properties of the crystals of monoclinic Rb 1- x Cs x D 2 PO 4 system were studied from -190°C to 120°C. The phase diagram of the system was established in the whole range of x . The crystal of x =0 has three phases denoted as I, II and III in order of the descending temperature. As x increases from zero, a ferroelectric IV phase appears between the phases III and II, and the temperature range of the phase TV spreads. The III–IV and IV–I transition entropies are distinctly small in comparison with those for the III–II, II–I and IV–II transitions.
在-190 ~ 120℃范围内，研究了单斜斜Rb 1- x Cs x d2po4体系晶体的介电、热释电和热性能。在整个x范围内建立了系统的相图。x =0的晶体有三个相，按温度递减的顺序分别为I、II、III。当x从0开始增大时，在III相和II相之间出现铁电相IV，相TV的温度范围扩大。III-IV和IV-I的过渡熵明显小于III-II、i - i和IV-II的过渡熵。
{"title":"Dielectric Studies of Monoclinic Rb 1− x Cs x D 2 PO 4 on the Phase Transitions","authors":"M. Sumita, T. Osaka, Y. Makita","doi":"10.1143/JPSJ.53.2784","DOIUrl":"https://doi.org/10.1143/JPSJ.53.2784","url":null,"abstract":"Dielectric, pyroelectric and thermal properties of the crystals of monoclinic Rb 1- x Cs x D 2 PO 4 system were studied from -190°C to 120°C. The phase diagram of the system was established in the whole range of x . The crystal of x =0 has three phases denoted as I, II and III in order of the descending temperature. As x increases from zero, a ferroelectric IV phase appears between the phases III and II, and the temperature range of the phase TV spreads. The III–IV and IV–I transition entropies are distinctly small in comparison with those for the III–II, II–I and IV–II transitions.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1984-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120947621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rayleigh and Brillouin scattering spectra of RbH 3 (SeO 3 ) 2 have been observed around the phase transition temperature T C . The temperature dependence of the Brillouin frequency shifts shows a small anomaly near T C in all three principal directions. The sound-velocity dispersion is found only in the c 55 transverse mode. The intensity of the Rayleigh component is insensitive to temperature even just near T C . The existence of dynamic clusters above T C is discussed and its characteristic frequency is roughly estimated, while static clusters are concluded not to exist in the same temperature region.
{"title":"Rayleigh and Brillouin Scattering in RbH 3 (SeO 3 ) 2 near the Phase Transition Temperature","authors":"A. Sakai, T. Yagi","doi":"10.1143/JPSJ.52.2544","DOIUrl":"https://doi.org/10.1143/JPSJ.52.2544","url":null,"abstract":"Rayleigh and Brillouin scattering spectra of RbH 3 (SeO 3 ) 2 have been observed around the phase transition temperature T C . The temperature dependence of the Brillouin frequency shifts shows a small anomaly near T C in all three principal directions. The sound-velocity dispersion is found only in the c 55 transverse mode. The intensity of the Rayleigh component is insensitive to temperature even just near T C . The existence of dynamic clusters above T C is discussed and its characteristic frequency is roughly estimated, while static clusters are concluded not to exist in the same temperature region.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1983-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122282465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to investigate the two-dimensionality and the easy plane anisotropy, the spin waves propagating along the [h, 0, 0], [h, h, 0], [h, 0.5h, 0] and [0, 0, l ] directions in CoBr 2 were observed using inelastic neutron scattering technique. The spin dynamics of CoBr 2 can be described by the anisotropic exchange Hamiltonian for S =1/2 with intraplanar exchange constants J 1 =2.01 meV, J 2 =0.019 meV and J 3 =-0.338 meV, interplanar exchange J '=-0.97 meV, and planar anisotropies D 1 =1.14 meV and D '=-0.06 meV. As shown by these numerical values, CoBr 2 has fairly strong XY characters, but the two-dimensionality is definitely poor. We point out, however, that in a planar antiferromagnet, the easy plane type anisotropy should remove the degeneracy of the excitation spectrum for the `in-plane' and the `out-of-plane' correlations, and in fact, these excitations are observed separately in this experiment.
{"title":"Neutron Scattering Investigation of the Magnetic Excitations in CoBr 2","authors":"H. Yoshizawa, Koji Ubukoshi, K. Hirakawa","doi":"10.1143/JPSJ.48.42","DOIUrl":"https://doi.org/10.1143/JPSJ.48.42","url":null,"abstract":"In order to investigate the two-dimensionality and the easy plane anisotropy, the spin waves propagating along the [h, 0, 0], [h, h, 0], [h, 0.5h, 0] and [0, 0, l ] directions in CoBr 2 were observed using inelastic neutron scattering technique. The spin dynamics of CoBr 2 can be described by the anisotropic exchange Hamiltonian for S =1/2 with intraplanar exchange constants J 1 =2.01 meV, J 2 =0.019 meV and J 3 =-0.338 meV, interplanar exchange J '=-0.97 meV, and planar anisotropies D 1 =1.14 meV and D '=-0.06 meV. As shown by these numerical values, CoBr 2 has fairly strong XY characters, but the two-dimensionality is definitely poor. We point out, however, that in a planar antiferromagnet, the easy plane type anisotropy should remove the degeneracy of the excitation spectrum for the `in-plane' and the `out-of-plane' correlations, and in fact, these excitations are observed separately in this experiment.","PeriodicalId":269857,"journal":{"name":"Tokyo Sugaku Kaisya Zasshi","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133975884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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