Magnetic and critical behavior studies of perovskite manganites La_0.8-xEu_xSr_0.2MnO₃(x = 0 and 0.05)

Effects of Eu doping at the A site on the magnetic properties of the perovskite manganite La_0.8-xEu_xSr_0.2MnO₃(x = 0 and 0.05)polycrystalline samples were investigated in this paper. The polycrystalline La_0.8-xEu_xSr_0.2MnO₃ (x = 0,0.05)samples were synthesized using a traditional solid-phase reaction method. X-ray diffraction (XRD) analysis of the polycrystalline samples did not indicate any impurities, confirming that the samples are single phase. The magnetization vs. temperature curve (M-T), as well as the magnetization vs. magnetic field curves (M-H) of the two samples, show that both synthesized structures are paramagnetic in the high-temperature region, while near the Curie temperature (Tc), the material is ferromagnetic. The Tc of both samples, La_0.8-xEu_xSr_0.2MnO₃ with x = 0 and the Eu³⁺-doped sample with x = 0.05, increased to 283 K and 284 K, respectively. The hysteresis loops of the samples show insignificant coercive force and no remanence. The inverse magnetic susceptibility vs. temperature curves (χ⁻¹-T, χ⁻¹ = H/M) indicate that the Griffiths phase temperature remains unchanged, while the Curie temperature decreases. The trends confirm that \({Eu}^{3+}\) doping changed the ferromagnetic coupling of the system. The average field model provides a good fit for the critical parameter response of both the parent and the doped synthesized material. At an applied field of 7 T, the change in magnetic entropy of the doped sample reaches its highest value at 4.19 J/kg·K, and the refrigeration efficiency is 445 J/kg. Our results show that the newly synthesized polycrystalline samples could be used as magnetic refrigeration materials.