6533b874fe1ef96bd12d6209

RESEARCH PRODUCT

Theory of domain structure in ferromagnetic phase of diluted magnetic semiconductors near the phase transition temperature

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description

We discuss the influence of disorder on domain structure formation in ferromagnetic phase of diluted magnetic semiconductors (DMS) of p-type. Using analytical arguments we show the existence of critical ratio $\nu_{\rm {cr}}$ of concentration of charge carriers and magnetic ions such that sample critical thickness $L_{\rm{cr}}$ (such that at $L \nu_{\rm {cr}}$ the sample is monodomain. This feature makes DMS different from conventional ordered magnets as it gives a possibility to control the sample critical thickness and emerging domain structure period by variation of $\nu $. As concentration of magnetic impurities grows, $\nu_{\rm {cr}}\to \infty$ restoring conventional behavior of ordered magnets. Above facts have been revealed by examination of the temperature of transition to inhomogeneous magnetic state (stripe domain structure) in a slab of finite thickness $L$ of p-type DMS. Our analysis is carried out on the base of homogeneous exchange part of magnetic free energy of DMS calculated by us earlier [\prb, {\bf 67}, 195203 (2003)].