Large magnetocaloric effects over a wide temperature range in MnCo1-xZnxGe

The magnetic and structural transitions can be controlled to coincide by partial substitution of Zn for Co in MnCo1-xZnxGe, leading to a large magnetocaloric effects over a wide temperature range. The magnetostructural transition from paramagnetic to ferromagnetic state results in magnetic entropy changes (-Delta S-M) of 26 J/kg K at 327K for Delta H = 5 T in the case of x = 0.045. Interestingly, a structurally driven first-order phase transition between two high magnetization states as observed for x = 0.05 and 0.06 also lead to large values of -Delta S-M = 31.4 and 20.6 J/kg K for Delta H = 5 T at 281 and 209 K, respectively. The observed large magnetocaloric effects with tunable phase transition temperatures make these materials promising for near room-temperature magnetic cooling applications. (C) 2013 American Institute of Physics.