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Effect of low doped calcium concentration to the magnetic properties of La0.7Ba0.3MnO3 material has been reported in this paper. This compound was chosen because it has high potential to be applied in electronic devices. The most intensive research in the last decade is about magnetocaloric effect (MCE). Magnetic refrigeration will replace Freon R12 that is used in conventional refrigeration with magnetic material which has MCE properties. It is due to conventional refrigeration produce chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFCs) gases which causes ozone depletion. The magnetic measurement was performed by using Vibrating Sample Magnetometer in the range of temperature between 300-400 K under external magnetic field until 20 kOe. By using derivative of magnetization as a function of temperature of the material’s result, Curie temperature (Tc ) of the material is 332.7 K. By using equation (5) for calculating magnetic field dependence of magnetization at various temperature result, magnetic entropy change value (ΔSM ) of the material can be obtained. The ΔSM of the material is -2.928 Jkg-1K-1. The material has highest magnetic entropy change value around its Tc . It is due to there is strong lattice spin coupling around its Tc and would be weak at below and above its Tc .

The structure, morphology, electrical transport and magnetoresistance properties of La0.7Ba0.1Sr0.2Mn0.9Cu0.1O3 has been investigated. The sample has been successfully prepared using sol-gel method. Structural investigation using X-ray diffraction (XRD) shows that the sample crystallizes in rhombohedral structure with R3c space group. The surface morphology of the sample shows that the sample consists of irregular polygonal grain. Furthermore, resistivity measurement shows that the sample undergoes a transition from metal to semiconductor behaviour upon heating. The electrical properties of the sample follow the electron-phonon-magnon scattering theory. Under the influence of the external magnetic field, the sample shows that up to 8% of the resistivity decreased at 200 K.

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