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 SM) 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 SM = 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.
Samanta, Tampas, Dubenko, Igor, Quetz, Abdiel, Stadler, Shane and Ali, Naushad. "Large Magnetocaloric Effects over a Wide Temperature Range in MnCo1-xZnxGe." (May 2013).