Large magnetocaloric effect and critical behavior in Sm

The magnetic properties and magnetocaloric effect (MCE) in electron-doped Sm0.09Ca0.91MnO3 nanomanganite have been investigated in detail by magnetization and heat capacity measurements. The maximum magnetic entropy change $(|\Delta S_{\text{M}}|)$ and the relative cooling power (RCP) are found to be, respectively, $8.59\ \text{Jkg}^{-1}\text{K}^{-1}$ and $1522\ \text{mJ/cm}^{3}$ for a 7 T magnetic field change along with a negligible hysteresis loss, making of this material a promising candidate for magnetic refrigeration at low temperature. The maximum value of $|\Delta S_{\text{M}}|$ occurs close to the Curie temperature $(T_{\text{C}})$ . The values of $|\Delta S_{\text{M}}|$ and RCP are comparable to a few hole-doped manganite. To investigate the nature of the paramagnetic-to-ferromagnetic phase transition, critical exponent study has been carried out. Based on the modified Arrott plot, we have determined the values of critical parameters ($T_{\text{C}},\beta,\gamma$ and δ) and conclusively shown that Sm0.09Ca0.91MnO3 has nearly mean-field–like long-range interaction. The calculated values of critical exponents not only obey the scaling hypothesis, but also corroborate the results obtained employing the Kouvel-Fisher method. The re-scaled magnetic entropy change curves for different applied magnetic fields collapse into a single master curve for this electron-doped manganite indicating clearly a second-order magnetic phase transition. Such noticeably large $|\Delta S_{\text{M}}|$ at low magnetic field makes this material a potential candidate for low-temperature magnetic refrigeration