Reversible room-temperature magnetocaloric effect with large temperature span in antiperovskite compounds Ga1−xCMn3+x (x=, 0.06, 0.07, and 0.08)

The magnetic and magnetocaloric properties of Ga1−xCMn3+x have been investigated. Reversible magnetocaloric effect (MCE) occurs near the Curie temperature TC. With increasing x, we find that the magnetic entropy change −ΔSM decreases while TC and magnetization increase. Meanwhile, the temperature span of −ΔSM versus T plot becomes well broadened. Due to the competition between the broadening temperature span and decreasing −ΔSM, the relative cooling power (RCP) increases initially and then decreases with increasing x further. The largest RCP (2.1 J/cm3 in a magnetic field of 45 kOe) observed at x=0.07 (TC=296.5 K) is comparable with the contemporary magnetic refrigerant materials. Considering the reversible MCE, inexpensive and innoxious raw materials, our result suggests that Ga1−xCMn3+x can be a promising candidate for magnetic refrigeration around room temperature.