Magnetocaloric effect in La0.7 NdxBa(0.3-x)MnO3 (x = 0, 0.05, 0.1) perovskite manganites

We have synthesized La0.7 NdxBa(0.3-x)MnO3 (x = 0, 0.05, 0.1) perovskite manganites by using sol-gel method and investigated structure, magnetic and magnetocaloric properties. Structural analysis revealed that La0.7Ba0.3MnO3 and La0.7Nd0.05Ba0.25MnO3 have cubic and La0.7Nd0.1Ba0.2MnO3 rhombohedral structure. The Curie temperature of the samples decreased with increasing Nd content and equals to 303, 293 and 257 K for x = 0, 0.05, 0.1, respectively. We present experimentally by using magnetization isotherms and heat-capacity measurements that room temperature magnetic refrigeration is successfully achieved for La0.7Nd0.05Ba0.25MnO3 structure by tuning the Mn3+ to Mn4+ ratio. Additionally, zero-field and field-dependent heat-capacity measurements were compared to investigate the accuracy of the value of the adiabatic temperature-change.