1990 Fiscal Year Final Research Report Summary
Fabrication of Metastable Solid Solution in Rare Earth-Transition Metal Alloys, and Their Magentic Properties
| Project/Area Number |
01550501
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | Tohoku University |
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Principal Investigator |
ISHIO Shunji Tohoku University, Faculty of Engineering, Lecturer, 工学部, 講師 (90134006)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Masateru Nagoya Institute of Technology Associate Professor, 助教授 (10091745)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Metastable Solid Solution / Rare Earth-Transition Metal Alloy / Amorphous / Magnetism |
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| Research Abstract |
Gd-Fe, Gd-B, C and (Gd, Tb-Fe)_<80>Si_<12>B_8 metastable solid solutions were prepared by rapidly quenching from melts. X-ray analysis, electron microscope observation, magnetic measurements, and Mossbauer spectroscopy were carried out to make clear the structure and magnetism of rare earth metal- transition metal metastable solid solutions.
1. Gd_xFe_<1-x>
X-ray structural analysis revealed that, while the hcp solid solution is formed at X<greater than or equal>0.7, the amorphous state is at 0.2<less than or equal>X<less than or equal>0.6. Both the amorphous alloy and hcp solid solution are ferrimagnet. Curie temperature Tc of the solid solution (X<greater than or equal>0.7) increases with an decrease of X, and becomes close to Tc of the amorphous state (0.2<les
2. Gd_<chi>B_<1-chi>
While the substitutional solid solution is formed at X<greater than or equal>0.8, the amorphous state is at X<0.8. The lattice constant C decreases with a decrease of X in the solid solution. The solid solutio
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n is a ferromagnet, whose Curie timperature Tc is close to Tc of hcpGd. The amorphous state is also ferromagnet, whose Curie temperature Tc is lower than that of hcpGd because of a random s
3. (Gd_<chi>Fe_<1-x>)_<80>Si_<12>B_8
The amorphous phase is formed at 0.7<less than or equal>X<less than or equal>1.0. Exchange interactions J between Gd magnetic moments are considered to distribute widely from negative to positive because of a random structure and an oscillating RKKY interaction. This distribution of J causes an instability of ferromagnetism. Fe magnetic moments in (Gd_<1-x>Fe_x)_<80>Si_<12>B_8 strongly couple with neighboring near Gd magnetic moments, make Gd-Gd interactions positive and stabilize a ferromagnetism. Mossbauer spectroscopy showed that an internal magnetic field is about 100kOe at X=0.7, indicating an apparent decrease of magnetic moment from 2.2mu_B for alphaFe to about 1.0mu_B for X=0.7. In (Tb_<chi>Fe_<1-x>)_<80>Si_<12>B_8, the amorphous phase is formed in 0.7<less than or equal>X<less than or equal>1.0. The amorphous alloys show a spin-glass like behavior giant local magnetic anisotropy of Tb atoms. Less
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