Abstract
Structural, magnetic, magnetocaloric, electrical properties, and spin-polarized tunneling effect in La0.5Ca0.3Te0.2MnO3 polycrystalline were studied in details. The temperature dependence of the inverse of the magnetic susceptibility indicates the presence of ferromagnetic exchange interaction between the nearest neighbors at the Weiss temperature theta(p)=265.32 +/- 0.109. Based on the magnetic field dependence of magnetization, M(H), and employing the thermodynamic Maxwell equation, the magnetic entropy change |Delta S-M| of the studied sample was determined. The maximum entropy change value of the system was around 4.99Jkg(-1)K(-1) under a magnetic field of 5T. Electrically, the upturned region of resistivity was observed at low temperature. The recovery of the resistivity was found to be strongly affected by the external magnetic field. The electrical data were analyzed considering various models. Interestingly, the exception of the spin-polarized tunneling (SPT) model is in good agreement with the experimental data among other models. In the current work, the SPT is the dominant mechanism leading to the rise of resistivity, while decreasing the temperature values. Magnetotransport analysis was successfully carried out using percolation model in the temperature range between around 50K to nearly 300K under different magnetic fields up to 8T. The isothermal field dependence of magnetoresistance was recorded fairly well via a phenomenological model based on the spin-polarized tunneling model.