The Study Of Ferro And Antiferromagnetism In Diluted Magnetic Semiconductor Gamnas

The prospect of a new generation of electronic devices based on the fundamental quantum property ofrnangular momentum, known as spin, has led to the rapidly developing field of spintronics. . These materialsrnare created by using molecular beam epitaxy (MBE) to incorporate into traditional semiconductors a quantityrnof transition metal atoms sufficient that ferromagnetism is exhibited.rnWe present first principles calculations for prospective magnetic materials for future applications in spintronics.rnThe material studied is focused on dilute magnetic semiconductors (DMS) like Ga1−x Mnx As that play arnkey role in semiconductor spintronics. Due to their ferromagnetic properties they can be used in magneticrnsensors and as spin injectors. The basic problem for applications are, however, the relatively low Curierntemperatures of these systems. We therefore focus on understanding the magnetic properties and on a reliablerncalculation of Curie temperatures from first principles. We have developed a theoretical framework forrncalculating critical temperatures by combining first principles calculations and in terms of the Ruderman–rnKittel–Kasuya–Yosida quantum spin model in Green’s function approach. Random distributions of thernmagnetic atoms are treated by using an analytical average of magnetic configuration are performed using greenrnfunction formalism using the dispersion relation for k2 for antiferromagnetic case and k for ferromagneticrncase . temperature dependencies of the spin wave specific heat,inverse magnetic susceptibility and reducedrnmagnetization are determined .the result shows Trn3rn2 dependence of for magnon specific heat in ferromagneticrncase and formulaformula T3 in antiferomagnetic,the dependence of the Neel temperature on the manganesernion concentration is linear thus for our calculation the highest Neel temperature obtained T=36.5k with in thernconcentration of 0.05 ,the reciprocal susceptibility increases linearly with increasing temperature above 173k

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