2004 Fiscal Year Final Research Report Summary
Meta-magnetism in Uranium-base Ferromagnetic Superconductors by Magnetic Compton Scattering
| Project/Area Number |
15540356
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Japan Synchrotron Radiation Research Institute |
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Principal Investigator |
SAKURAI Yoshiharu Japan Synchrotron Radiation Research Institute, Materials Science Division, Inelastic Scattering Team, Team Leader, Senior Scientist, 利用研究促進部門I・非弾性散乱チーム, チームリーダー主幹研究員 (90205815)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Etsuji Japan Synchrotron Radiation Research Institute, Advanced Science Research Center, Scientist, 先端基礎研究センター, 副主任研究員 (50343934)
ITOU Masayoshi Japan Synchrotron Radiation Research Institute, Life and Environmental Science Division, Element Spectroanalysis Team, Associate Senior Scientist, 利用研究促進部門II・分析チーム, 副主幹研究員 (10344392)
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| Project Period (FY) |
2003 – 2004
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| Keywords | UGe2 / Magnetic Compton scattering / Superconductivity / Ferromagnetism / High Pressure |
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| Research Abstract |
Coexistence of ferromagnetism with superconductivity in UGe_2 has drawn much attention form many research scientists. The meta-magnetism observed in the ferromagnetic phase has been intensively studied in connection with the mechanism of the superconductivity. The aim of this project is to understand the meta-magnetism in an atomic-scale level by using the magnetic Compton scattering technique.
We have carried out magnetic Compton scattering experiments on ferromagnetic UGe_2 at ambient pressure and have not find any anomalies in spin moment across the meta-magnetic transition temperature of 32 K. By combining with the magnetization data available in literatures, we have successfully separated the spin and orbital moments. The ratio of orbital moment to spin moment (L/S) is determined to be almost constanat, L/S=-0.2〜-2.3,over the temperature range between 10 K and 60 K. In the line-shape of magnetic Compton scattering (magnetic Compton profile), however, we have found significant changes across the meta-magnetic transition.
In order to explain the origin of the changes observed in magnetic Compton profiles, we have fit atomic profiles of U-5f orbitals with different magnetic quantum number (m). The value of L/S predicted by the present fit is in good agreement with the above-mentioned, experimental values, showing the validity of the present model fitting.
The fitting results show that the observed changes in the magnetic Compton profiles are caused by the changes of the weight of the m=1 and m=2 orbital states, suggesting strong fluctuation in the hybridization with Ge p states.
In addition, we have performed high-pressure measurements at 1.0 GPa. The data-processing is in progress.
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