STUDY THE MAGNETOCALORIC EFFECT IN DILUTED MAGNETIC MANGANESE DOPED CADMIUM TELLURIDE (CD1-XMNXTE) QUANTUM WIRE | دراسة ظاهرة المغناطيسية الحرارية في السلك الكمي المكون من مادة Cd1-xMnxTe

This thesis presents a study for the Magnetocaloric effect of Cd1-xMnxTe magnetic nanomaterial. The Hamiltonian for an electron confined in a quantum wire, in the presence of an external magnetic field, and Rashba spin orbit interaction term had been solved. The obtained energy dispersion relation had been used to calculate: electronic structure and display Landau levels and density of states for different physical Hamiltonian parameters. The density of state function shows a significant dependence on spin, Rashba, exchange effect and magnetic field. We have computed the partition function, which is an essential step to calculate the magnetic and thermal quantities for QWW. We have shown dependence of magnetic properties like Magnetization and magnetic Susceptibility as function of magnetic field strength quantum wire radius, exchange and Rashba strength parameters. The computed results show that the material can display a phase transition between Paramagnetic and Diamagnetic types. We observed an oscillatory behavior in magnetic Susceptibility curve as a function of magnetic field calculated for different values of Rashba term quantum wire radius and magnetic exchange effect. This oscillating behavior is a result of Landau levels crossing in the quantum wire energy spectra. The behavior of the thermal properties like heat capacity and entropy have been investigated. This work includes a comprehensive study of magnetocaloric effect for this material at nanoscale. The obtained results for magnetocaloric effect reveal that the QWW made from Cd1-xMnxTe show an interesting MCE behavior at low temperature scale below 70K. QWW can absorb or release heat by switching the magnetic field on and off. The cooling/heating MCE process can be controlled by adjusting the physical parameters, like Rashba term, quantum wire radius, exchange term and magnetic field. These findings make our study attractive, and thus the selected magnetic wire material, good candidate for several future technological device applications for this type of magnetic nano material.