Magnetic Transition and Magnetocaloric Effect of Gd1−xNdxMn2Ge2 (x = 0.3 and 0.4) Compounds

Gd1−xNdxMn2Ge2 compounds with x = 0.3 and 0.4 were prepared by arc melting and crystallized in the ThCr2Si2-type structure with the space group I4/mmm based on X-ray powder diffraction (XRD) results. Magnetic transition and magnetocaloric effect (MCE) of the Gd1−xNdxMn2Ge2 compounds were investigated by magnetic measurements on a physical property measurement system (PPMS). Gd0.7Nd0.3Mn2Ge2 compound exhibits complicated magnetic transitions at around 63 K (Tcomp), 86 K (T1), 136 K (TC), 260 K (TNinter\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$T_{\mathrm {N}}^{\text {inter}}$\end{document}), and 347 K (TCinter\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$T_{\mathrm {C}}^{\text {inter}}$\end{document}), respectively, while Gd0.6Nd0.4Mn2Ge2 compound shows a spin re-orientation transition at about 52 K. Combined with isothermal magnetization curves and the Maxwell relation, the maximum magnetic entropy changes of Gd0.7Nd0.3Mn2Ge2 and Gd0.6Nd0.4Mn2Ge2 were calculated to be 4.31 and 5.15 J kg− 1 K− 1 under the applied magnetic field changing from 0 to 5 T, respectively.