The magnetisation and the correlation functions in thin diluted films (Ising model, S=¹/₂)

Abstract

The thin diluted ferromagnetic film with sc symmetry is considered in the thirdorder Matsudaira approximation. The equations for the description of magnetisation and various correlation functions have been derived and the results of the numerical calculations have been presented. In particular the critical temperature, the critical concentration, the magnetisation and various correlation functions are discussed in detail for various film thicknesses and for several magnetic atom concentrations.

Influence of structural short-range order on the phase diagram of diluted anisotropic Heisenberg ferromagnet

“…[1][2][3][4][5][6][7][8] Various magnetic systems have been studied, first of all the dilute bulk materials 1,7,9 but also the ternary alloys 10 and thin films 8 as well. In these investigations, numerous approximate methods have been employed, the main of which being the molecular-field approximation ͑MFA͒, 10 effective-field theory ͑EFT͒, 5,6,9,11,12 Bethe-Peierls-Weiss method, 1 or coherent-potential approximation ͑CPA͒.…”

Direct free energy minimization methods: application to grain boundaries

“…N ot only does this approxim ation ignore correlations in the occupancies of different sites but it also ignores self-correlations. Experience in magnetic systems (Balcerzak et al 1990), indicates th a t inclusion of self-correlations gives the largest correction to the m f a . Self-correlations refer to the fact th a t = (pj}, rather than < p f} = (pf)n which theory.…”

Magnetization distribution in a spin ladder-shaped quantum nanomagnet

“…The modeling of site-dependent magnetization as a function of the temperature and external magnetic field for cluster-like systems appears therefore well motivated and valuable, especially if based on the exact approach. We can mention that the theoretical studies of magnetization distribution (performed with either exact or approximate methods) are known in the literature both for zero-dimensional magnets [36] as well as for other non-uniform systems, like, for example, thin films [37][38][39]. Also the thermodynamics of magnetic clusters was subject of several computational works exploiting the exact (or close to exact) approaches, involving both 'classical', Isingbased systems [40][41][42][43][44][45] as well as highly non-trivial quantum Heisenberg systems [7,40,[46][47][48][49][50][51][52][53][54][55][56].…”