2003 Fiscal Year Final Research Report Summary
Development of Giant Magnetostrictive Material by Applying Metamagnetic Transition
| Project/Area Number |
13555168
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Tohoku University |
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Principal Investigator |
FUKAMICHI Kazuaki Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (00005969)
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| Co-Investigator(Kenkyū-buntansha) |
FUJITA Asaya Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (10323073)
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| Project Period (FY) |
2001 – 2003
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| Keywords | itinerant-electron metamagnetic transition / isotropic volume magnetostriction / hydrogen absorption / multiple magnetic phase transition / magnetovolume effect |
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| Research Abstract |
Research results of the present project is summarized as follows.
1 Study on Isotropic Giant Magnetostriction of Itinerant-Electron Metamagnetic La (Fe_xSi_<1-x>)_<13> Compounds
La(Fe_xSi_<1-x>)_<13> Compounds (0.86【less than or equal】x【less than or equal】0.90) exhibit the itinerant-electron metamagnetic transition just above the Curie temperature Tc〜200K. Volume change of about 1.5% is caused by a change in magnetization of about 1μ_B at the transition. To apply the volume change to magnetostrictive materials, the Curie temperature was controlled up to room temperature by hydrogen absorption. For La (Fe_<0.88>Si_<0.12>)_<13>H_<1.0> compound, the value of T_c was elevated up to 278 K, and large isotropic volume magnetostriction comparable in that of conventional Tafenol has been observed around room temperature. Since, the magnetostriction of La (Fe_xSi_<1-x>)_<13>H_y compounds show both the large magnitude comparable to those to the conventional materials and the isotropic feature, the
… More
compounds can be new magnetstrictive materials which remove the process such as the structural control in constructon of devices.
2 Study on Magnetovolume Effect and Magnetostriction in La (Fe_xAl_<1-x>)_<13> Compounds showing Multiple Magnetic Phase Transition
La (Fe_xAl_<1-x>)_<13> Compounds are ferromagnetic in 0.60【less than or equal】x【less than or equal】0.86, while become antiferromagnetic in 0.87【less than or equal】x【less than or equal】0.92. Furthermore, the magnetic field induced first-order transition to the ferromagnetic state appears in the antiferromagnetic phase. In addition, the thermal induced first-order transition has been observed at the transition temperature T_0 in 0.86<x<0.87. In the itinerant-electron magnets, amplitude of magnetic moment varies in these phase transition followed by volume change. By thermal expansion measurement around T_0, the isotropic volume change of about 0.5 % has been observed. Furthermore, it has been confirmed that the isotropic volume magnetostriction is induced by the magnetic field induced antiferromagnetic-ferromagnetic transition for x = 0.88. Consequently, it has been demonstrated that large isotropic volume magnetostriction is appeared by significant change in amplitude of magnetic moment due to the various magnetic phase transitions in the present compounds. Less
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Research Products
(14 results)
