Magnetocaloric effects and reduced thermal hysteresis in Si-doped MnAs compounds

The magnetocaloric effects in MnAs1−xSix (x = 0.03, 0.06 and 0.09) compounds have been investigated. The Curie temperature can be tunable in a wide range by changing the Si content. With increasing Si doping, the thermal hysteresis is decreased to nearly zero (x > 0.06) and the metamagnetic transition becomes ambiguous, being a second-order-like one. The maximum of the magnetic entropy change is maintained above 10 J kg−1 K−1 and 5 J kg−1 K−1 in MnAs1−xSix for the field change of 5 T and 2 T, respectively. These results indicate that the Si-doped MnAs compounds with reduced thermal hysteresis are potential candidates of the room-temperature magnetic refrigeration.