Spin orientation and magnetostriction of Tb1−xDyxFe2 from first principles
The optimal amount of dysprosium in the highly magnetostrictive rare-earth compounds Tb1−xDyxFe2 for room-temperature applications has long been known to be x = 0.73 (Terfenol-D). Here, we derive this value from first principles by calculating the easy magnetization direction and magnetostriction as...
| Main Authors: | , , |
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| Format: | Journal article |
| Jezik: | English |
| Izdano: |
American Physical Society
2020
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| Izvleček: | The optimal amount of dysprosium in the highly magnetostrictive rare-earth compounds Tb1−xDyxFe2 for room-temperature applications has long been known to be x = 0.73 (Terfenol-D). Here, we derive this value from first principles by calculating the easy magnetization direction and magnetostriction as a function of composition and temperature. We use crystal-field coefficients obtained within density-functional theory to construct phenomenological anisotropy and magnetoelastic constants. The temperature dependence of these constants is obtained from disordered-local-moment calculations of the rare-earth magnetic order parameter. Our calculations find the critical Dy concentration required to switch the magnetization direction at room temperature to be xc = 0.78, with magnetostrictions λ111 = 2700 and λ100 = −430 ppm, close to the Terfenol-D values. |
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