Effect of Co doping on the structural, magnetic and electron transport properties of Mn$_{2}$PtSn Heusler alloy

Materials with high magnetic anisotropy and Curie temperature well above room temperature have huge potential for a range of applications including permanent magnet, high density recording and spintronic devices. Tetragonal Mn$_{2}$PtSn is one such Heuslar compounds which has been predicted to have very high magnetic anisotropy but its low Curie temperature (T$_{\mathrm{c}}=$ 374 K) is a drawback [1]. Our experimental investigation of the rapidly quenched nanostructured ribbons shows that a single phase Mn$_{2}$PtSn in the tetragonal structure cannot be easily prepared without the substitution of an external element. We have found that a partial replacement of Pt with Co in Mn$_{2}$PtSn stabilizes the tetragonal structure and also improves the magnetic properties. The experimentally observed values of the room-temperature saturation magnetization (M$_{\mathrm{s}}$) and Curie temperature (T$_{\mathrm{c}}$) are respectively 35 emu/g and 385 K for Mn$_{2}$PtSn and 43 emu/g and 516 K for Mn$_{2}$Pt$_{0.3}$Co$_{0.7}$Sn. The effect of cobalt on the magnetic anisotropy and electron transport properties of this material will be discussed.\\[4pt] [1] J. Winterlik et al., Adv. Mater. \textbf{24}, 6283 (2012).