Magnetic Properties and Magnetic Entropy Changes of Eu-Doped La0.9Sr0.1MnO3 Perovskite Manganese Oxides

Polycrystalline samples of La 0.9− x Eu x Sr 0.1 MnO 3 ( x = 0.00, 0.05) were prepared using the standard solid-state reaction method. The effects of Eu 3+ doping on the magnetic properties, magnetic entropy changes, and critical behaviors of La 0.9 Sr 0.1 MnO 3 polycrystalline samples were systematically investigated. Preformed cluster phases were present in both samples in the temperature ranges of 118–326 K and 121–329 K, respectively. Additionally, near the Curie temperature ( T C ), the samples exhibited a second-order transition. The critical behaviors of the two samples were best fitted with the mean field model. The maximum magnetic entropy changes Δ S M of the two tested samples at 7 T near T C were 2.76 J K −1 kg −1 and 2.53 J K −1 kg −1 , respectively; in addition, their relative cooling power was 425.28 J kg −1 and 354.93 J kg −1 , respectively. The maximum magnetic entropy change calculated from the fitted data was in close agreement with the experimental data. These results indicate that the samples have the potential to realize magnetic refrigeration in the high-temperature regime ( T > 77 K).