Title: Study of magnetic anisotropy in rare-earth transition-metal permanent magnets

Speaker: Dr. Santosh Kumar, Warwick University

Abstract: The microscopic origin of permanent magnetism is magnetocrystalline anisotropy which is often explained in terms of ferromagnets. However, the best performing permanent magnets based on rare-earth and transition-metals (RE-TM) are ferrimagnets comprising various magnetic sublattices. We have shown [1] that the calculation of magnetocrystalline anisotropy of a ferrimagnet GdCo5 yields higher numbers at 0 K and exhibit wrong temperature-dependence. To solve this problem, we have introduced a first principles approach [1] to calculate the magnetization vs field (FPMVB) curves mirroring the experiments actually used to determine the anisotropy. In this talk, I will be discussing about our new experimental results [1] obtained on the single crystals of two of the permanent magnets YCo5 and GdCo5 grown using optical floating zone technique [2]. Our experimental findings are found to be in good agreement with the FPMVB approach. Through a combination of calculations and measurements, we provide the missing link between the electronic structure theory and the practical measurements of magnetocrystalline anisotropy.

References-

1. C. E. Patrick, Santosh Kumar et al. Phys. Rev. Lett. 120, 097202 (2018).

2. C. E. Patrick, Santosh Kumar et al. Phys. Rev. Mater. 1, 024411 (2017).