Magnetic and magnetocaloric properties of DyCo2Cx alloys

Abstract The magnetic and magnetocaloric properties of DyCo 2 C x ( x  = 0, 0.05, 0.1, and 0.15) alloys were investigated. The results show that the Curie temperature (T C ) of the DyCo 2 C x alloys increases with increasing C content, from 136 K ( x  = 0) to 152 K ( x  = 0.15), but the lattice parameter a of DyCo 2 C x exhibits a maximum at x  = 0.05. The suppression of the ac susceptibility of DyCo 2 C x at low temperature indicates the enhancement of the domain wall pinning effect by carbon doping. The positive slops of the Arrott plots of the doped compounds indicate that the phase transition is second order for the carbon-doped alloys, and the maximum value of the isothermal magnetic entropy change (Δ S M ) for the magnetic field change of 50 kOe decreases from −13.9 J/kg· K ( x  = 0) to −7.8 J/kg·K ( x  = 0.15). The relative cooling power (RCP) of DyCo 2 C x is nearly the same in all studied alloys, while the temperature-averaged entropy change over 10 K temperature span, TEC(10), indicates decreasing magnetocaloric performance of carbon doped materials.