Magnetic structure of films: Dependence on anisotropy and atomic morphology

摘要: Abstract In this review a number of magnetic properties different thin film systems are investigated as functions the temperature and atomic morphology. Special attention is paid to determine influence collective excitations noncollinear structure. At finite temperatures these problems studied within Heisenberg model by application mean field approximation well many-body Green’s function theory. First, magnetization profiles ordering (Curie-) calculated for systems. particular, single ferromagnetic (FM) films, coupled bilayers with two FM trilayers consisting films separated nonmagnetic spacer layer studied. Here role fluctuations highlighted, which particularly important low-dimensional magnets. For under consideration we show that strongly varying caused already weak interlayer couplings can be explained only taking into account excitations. Hence, effect two-dimensional magnets explicitly. The results partly compared measurements. Moreover, thin-film structure materials helical bulk investigated. We due breaking nearest- next-nearest-neighbor bonds in surface region of, e.g., Ho becomes significantly disturbed. Even phase may result decreasing thickness or an increasing temperature. possibility paramagnetic ordered pointed out. addition, spin reorientation transition temperature, thickness, external field. This phenomenon from competing effective anisotropy contributions dependence on example. investigate noncollinearities roughness variation thickness. much broader one smooth film. feature considered higher-order anisotropies otherwise collinear magnetization. Approximate expressions quantities presented. inhomogeneous system profile during SRT exhibits behavior, hence not characterized domains comparatively domain walls. reversal induced transversal simple cases antiferromagnetic (AFM) monolayers. latter case strength component perpendicular maximum. unexpected property presence quantum antiferromagnets. Finally, FM–AFM layers coupling induces net binding energy thus interface layer. A AFM possibly also close interface. resulting temperature(s) depend sensitively lattice symmetry. importance enhance total subsystem. Alternatively, if competes intrinsic anisotropy, take place