Giant room-temperature magnetocaloric effect in Mn1−xCrxAs

A giant magnetocaloric effect was observed at room temperature in Mn1−xCrxAs compounds with x=0.006 and 0.01. The Cr dopant reduces (or even eliminates) the large thermal hysteresis of MnAs, while it lowers the first-order transition temperature from 313K for MnAs to 265K for Mn0.99Cr0.01As. Near the Curie temperature, a magnetic field induces a first-order phase transition from a ferromagnetic hexagonal phase to a paramagnetic orthorhombic phase, leading to a maximum value of ΔSM of 20.2J∕kgK at 267K for a 5T field change for Mn0.99Cr0.01As. The study on the Mn1−xCrxAs system may open an important field in searching proper materials for room-temperature magnetic refrigeration.