Magnetic critical behavior and giant magnetocaloric effect in co-doping multiphase Gd1−xDyxCrO3 composites

The critical behavior and magnetocaloric effect (MCE) of Gd1−xDyxCrO3 (0 ≤ x ≤ 1) (GDCO) prepared by solid-state sintering method were investigated. XRD patterns and Rietveld refinement, SEM and EDS measurements show that the samples are multiphase composite, consisting of Gd/Dy-rich and co-doping GDCO phases. The zero field cooling (ZFC) and field cooling (FC) curves confirm the presence of multiphase transition temperatures: TNR(R = Gd1−xDyx) and TNCr, with a spin reorientation temperature (TSR) for Gd-rich GDCO. The critical parameters are derived by the modifying Arrott plots, showing the magnetic interactions of DGCO changed from long-range order to short-range order and the magnetic order decreased. The maximum value of the magnetic entropy change (-∆SMmax) and relative cooling efficiency (RCP) for the DGCO samples could be tuned from 35.6 to 16.3 J/kg K (3.6 to 7.3 J/kg K) and from 356.7 to 341.7 J/kg (32.4 to 43.8 J/kg) at 5 T (1 T) applied magnetic field, respectively. The large values of -∆SM and RCP shows that DGCO is a good candidate in the low temperature magnetic refrigeration region.