INVESTIGATION OF THE STABILITY AND SPINTRONIC PROPERTIES OF NbRhGeX (X= Cr, Co, Mn, Fe, Ni) ALLOYS

Abstract

The traditional no volatile memory devices such as the Hard Disk Drives (HDDs), are made with magnetic merils and as such , likely to loose their content under sufficient magnetic field or thermal fluctuation. For high density data stability, and dynamic low power consumption, the use of both electronic charges and magnetic spins (Spintronics) have been canvassed. The numerical calculation of the spintronic property of NbRhGeX(X=Cr, Co, Fe, Mn, Ni) in the full Huesler structure using the Generalized Gradient Approximation of the Density Functional Theory (DFT). The formation/cohesive energies, elastic tensors, magnetic moments and the band structure of each composition were evaluated using the Quantum Espresso ab-initio computer code. The formation energies are negative for NbRhGeCr (-0.06 Ry), NbRhGeCo (-0.106 Ry), NbRhGeFe (-0.104 Ry) and NbRhGeNi (-0.101 Ry) while it is positive for NbRhGeMn (0.647 Ry) indicating that NbRhGeMn is not thermodynamically feasible. The elastic tensors predicts that NbRhGeFe and NbRhGeCo are elastically stable while NbRhGeCr, NbRhGeMn, NbRhGeNi are not. Evaluation of the electronic structures reveals that NbRhGeFe and NbRhGeCo have the 100% spin polarization required of a material for spintronic application. The Density of States analysis predicts strong ferromagnetism in NbRhGeCo (1.48μ B ) and NbRhGeFe (1.63μ B ) while NbRhGeMn (0.45μ B ) and NbRhGeCr (0.01μ B ) are weak ferromagnets and NbRhGeNi (0.00μ B ) is nonmagnetic. Overall, only NbRhGeFe is predicted suitable for spintronic application based on its account of suitable formation energy, stable elastic constants, structural stability and strong magnetic property.