Tuning of the Magnetocaloric Properties of Mn5Ge3 Compound by Chemical Modification

The rare earth-free Mn5Ge3 compound shows magnetocaloric properties similar to those of pure Gd; therefore, it is a good candidate for magnetic refrigeration technology. In this work, we investigate the influence chemical substitution on crystal structure and magnetic, thermodynamic, polycrystalline prepared by induction melting. For purpose, replaced 5% Mn with Cr or Co Ge B Al. additional elements were shown not change parent (space group P63/mcm, No. 193). case properties, all samples remained ferromagnetic ordering temperature (TC) lower than original (TC = 295(1) K). exception was sample B, where observed an increase in TC 3 K. maximum value entropy change, |∆Sm|MAX (for field 5 T), decreased from 7.1(1) 6.2(1), 6.8(1), 4.8(1), 5.8(1) J kg−1 K−1 alloys Al, Cr, Co, respectively. adiabatic (∆Tad) 1 T) determined specific heat measurements equal 1.1(1), 1.2(1), 0.8(1), 0.8(1) K Mn5Ge3, Mn5Ge2.85B0.15, Mn5Ge2.85Al0.15, Mn4.75Cr0.25Ge3, Mn4.75Co0.25Ge3, obtained data compared literature. It found that allowed tuning wide range. At same time, reduction parameters’ values relatively small. Therefore, produced Mn5Ge3-based allow expansion operation range as material.