LAUSR

We report results of the magnetization and magnetocaloric effect in lightly Ga-doped perovskite manganites Nd0.55Sr0.45Mn0.98Ga0.02O3. It undergoes a second-order paramagnetic to ferromagnetic transition at TC = 250 K and shows a strong ferromagnetic properties below TC. However, an obvious upward deviation from the Curie-Weiss law far above TC indicates the existence of non-Griffiths-like behavior in paramagnetic phase. Together with the measurements of isothermal magnetization around the Curie temperature, the unsaturated magnetization curves under high magnetic field of 7.0 T imply that the Ga-substitution causes the formation of antiferromagnetic phase due to some localized charge order phases generated in this composition. Based on the data of isothermal magnetization measured around TC and Maxwell relation, we have calculated the maximum isothermal magnetic entropy change of 6.23 J/kg K for Δμ0H = 7.0 T magnetic field variation. Though only a moderate magnetic entropy change were obtained, a considerable large relative cooling power of 260 J/kg for Δμ0H = 7.0 T and 182 J/kg for Δμ0H = 5.0 T were found in this sample, this ensure it to be a potential candidate material to be applied in the magnetic refrigeration.