Tuning the magnetic transition and magnetocaloric effect in Mn1-xCrxCoGe alloy ribbons

The Mn1-xCrxCoGe (x = 0.01, 0.015, 0.02, 0.03) alloy ribbons are prepared. The microstructure, structure, magnetic and magnetocaloric properties were studied in these ribbons. The substitution of Cr for Mn effectively reduces the structural transformation temperature of MnCoGe alloy. In annealed Mn0.98Cr0.02CoGe ribbons, a coupled magnetostructural transformation from the ferromagnetic TiNiSi-type to paramagnetic Ni2In-type state with the increasing temperature is observed. As a result, large magnetocaloric effect near room temperature and simultaneously almost zero magnetic hysteresis losses presented in these ribbons would be favorable to room-temperature magnetic refrigeration. In measuring the isothermal magnetization curves, both the loop and standard methods are adopted to compare and make sure the reliability of our results.