Pressure effect on the magnetic properties of the half-metallic Heusler alloyCo2TiSn

Abstract

Precise magnetization measurements of a half-metallic ferromagnet ${\mathrm{Co}}_{2}\mathrm{TiSn}$ with the Heusler type structure have been carried out under pressure up to 1.27 GPa. At ambient pressure, the spontaneous magnetic moment ${M}_{\mathrm{s}}^{\mathrm{exp}}$ and the Curie temperature ${T}_{\mathrm{C}}^{\mathrm{exp}}$ are experimentally obtained to be $1.993(3)\phantom{\rule{4pt}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$/f.u. and $376.76(7)$ K, respectively. The ${M}_{\mathrm{s}}^{\mathrm{exp}}$ is independent of applying pressure. The ${T}_{\mathrm{C}}^{\mathrm{exp}}$ decreases with the increase of pressure and the pressure derivative of the Curie temperature $d{T}_{\mathrm{C}}^{\mathrm{exp}}/dp$ is estimated to be $\ensuremath{-}3.15(9)$ K/GPa. Furthermore, the pressure effect on the electronic and magnetic properties of ${\mathrm{Co}}_{2}\mathrm{TiSn}$ has been theoretically investigated on the basis of first-principles density functional calculations by using the projector augmented wave method in order to evaluate the half metallicity of ${\mathrm{Co}}_{2}\mathrm{TiSn}$. Both the experimental and the theoretical results under pressure reveal that ${\mathrm{Co}}_{2}\mathrm{TiSn}$ is half metal. The experimental results of pressure-dependent magnetic properties are finally discussed on the basis of the spin fluctuation theory for itinerant electron magnetism.