Cubic Laves ferromagnetTbNi2Mninvestigated through ambient-pressure magnetization and specific heat and high pressure ac magnetic susceptibility

Abstract

$\mathrm{Tb}{\mathrm{Ni}}_{2}\mathrm{Mn}$ is a cubic Laves material, isostructural to $\mathrm{Tb}{\mathrm{Ni}}_{2}$, with the Mn sitting on both the Tb and the Ni lattice positions. It is ferromagnetic at ambient pressure at ${T}_{C}=151\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and has been investigated in detail at ambient pressure through magnetization and specific heat with various applied magnetic fields. It displays Curie-Weiss behavior above ${T}_{C}$, with an effective moment of $8.43{\ensuremath{\mu}}_{B}∕\mathrm{f.u.}$, and isothermal magnetization at various temperatures is consistent with narrow domain walls. The low-temperature specific heat results in a linear contribution of $65\phantom{\rule{0.3em}{0ex}}\mathrm{mJ}∕\mathrm{mol}\phantom{\rule{0.2em}{0ex}}{\mathrm{K}}^{2}$ and a Debye temperature of ${\ensuremath{\theta}}_{D}=188\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The ac magnetic susceptibility has been investigated using designer diamond anvils up to $28.3\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. A magnetic anomaly at ${T}^{*}$ is investigated as a function of both magnetic field and pressure, both of which have very little effect for fields less than the coercive force. The Curie temperature decreases at a rate of $d{T}_{C}∕dP=\ensuremath{-}1.96\phantom{\rule{0.3em}{0ex}}\mathrm{K}∕\mathrm{GPa}$, and differences between hydrostatic and nonhydrostatic conditions are discussed.