2002 Fiscal Year Final Research Report Summary
Theory of Ordered State of Multiparty Freedoms of Atoms and X-Ray Spectroscopy and Scattering
| Project/Area Number |
13640365
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体物性Ⅱ(磁性・金属・低温)
|
|---|
| Research Institution | HIROSHIMA UNIVERSITY |
|---|
Principal Investigator |
JO Takeo Advanced Sciences of Matter, Department of Quantum Matter, Professor, 大学院・先端物質科学研究科, 教授 (20093487)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHIMAHARA Hiroshi Advanced Sciences of Matter, Department of Quantum Matter, Associate Professor, 大学院・先端物質科学研究科, 助教授 (40226220)
TANAKA Arate Advanced Sciences of Matter, Department of Quantum Matter, Research Associate, 大学院・先端物質科学研究科, 助手 (70253052)
|
|---|
| Project Period (FY) |
2001 – 2002
|
| Keywords | x-ray linear dichroism / resonant x-ray scattering / perovskite / vanadium oxides / spin-orbit interaction / ペロフスカイト / ヴァナジウム酸化物 / スピン軌道相互作用 |
|---|
| Research Abstract |
(1) Orbital States in Perovskite-Type Transition-Metal Oxides and X-Ray Absorption Linear Dichroism
We investigated the effect of 3d spin-orbit interaction in V ion in vanadium perovskite-type oxides including LaVO3 and YVO3 on the basis of the perturbation calculation with respect to the V-V Electron transfer and showed that the orbital magnetic moment of V can considerably contribute to the total moment. For YTi03, where in addition the ferromagnetic component in the c-direction, more-than-one kinds of antiferromagnetic modulations are observed in the ab plane, we proposed that a non-collinearity between the spin and orbital moments can explain the more-than-one additional modulations. We furthermore pointed out that the x-ray absorption on linear dichroism signal is to be observed in many perovskites with antihero-orbital orderings, which is in sharp contrast to the absence of x-ray absorption magnetic circular dichroism signal in antiferromagnets.
(2) Theory of Antiferromagnetic Ordering in V203
V203 is know to exhibit a metal-insulator transition with decreasing the temperature. In the low temperature antiferromagnetic phase, the crystal symmetry changes from the corundum structure in the high temperature phase to the monoclinic one and it shows anomalous magnetic structure reflecting the low symmetry crystal structure. We calculated, by extending the V-ion pair model, the exchange interaction between V-ion pairs and showed that the sign of the exchange interaction is sensitive to the lattice distortion and explain the magnetic ordering without assuming the so far proposed orbital-ordering model.
|
