Magnetocaloric Effect and Refrigerant Capacity of Non-Stoichiometric Single Crystalline

Non-stoichiometric Nd_0.5Sr_0.5MnO₃ (NSMO) single crystalline has been grown by the floating zone method. Their magnetic properties, magnetocaloric effect (MCE) and refrigerant capacity (RC) at near both first- and second-order phase transitions were investigated. The NSMO system goes through an antiferomagnetic charge-ordered transition at T_CO ~ 152 K followed by a ferromagnetic to paramagnetic transition at T_C ~ 272 K. The transition region spread over a broader temperature range at the T_C but it had a narrower temperature range at the T_CO. The maximum magnetic entropy change ΔS_max gives about 1.65 J · kg^-1 · K^-1 at the first order magnetic transition and -1.13 J · kg^-1 · K^-1 at the second order magnetic transition, respectively. RC is obtained and it shows much higher value about 34.85 J/kg at T_C than the RC 19.06 J/kg at T_CO. The slight non-stoichiometric NSMO single crystalline system raises the Curie temperature around 30 K towards room temperature without degradation of the RC and temperature span corresponding to the full width at half maximum of ΔS_max(ΔT_FWHM) compared to pure single crystalline NSMO system.