Theoretical simulation of the anisotropic phases of antiferromagnetic thin films

Abstract

We simulate antiferromagnetic thin films. Dipole-dipole and antiferromagnetic exchange interactions as well as uniaxial and quadrupolar anisotropies are taken into account. Various phases unfold as the corresponding parameters J, D, and C, as well as the temperature T and the number n of film layer, vary. We find ͑i͒ how the strength ⌬ of the anisotropy arising from dipole-dipole interactions varies with the number of layers away from the film's surface, with J and with n; ͑ii͒ a unified phase diagram for all n-layer films and bulk systems; ͑iii͒ a layer-dependent spin reorientation ͑SR͒ phase in which spins rotate continuously as T, D, C, and n vary; ͑iv͒ that the ratio of the SR to the ordering temperature depends ͑approximately͒ on n only through ͑D + ⌬ / n͒ / C, and hardly on J; ͑v͒ a phase transformation between two different magnetic orderings, in which spin orientations may or may not change, for some values of J, by varying n.

Equilibrium spin-glass transition of magnetic dipoles with random anisotropy axes on a site-diluted lattice

“…The boundary conditions as well as the L d box scheme we use here are as in Refs. [9,28,29]. Finally, it is worth recalling that thermal equilibrium results obtained for H=0 for large cubic-shaped systems can, by virtue of Griffiths theorem 30 be generalized to other shapes in three dimensions.…”

Exchange Bias Phenomenology and Models of Core/Shell Nanoparticles

“…138 228 In similar MC simulations, Billoni et al 229 have studied the influence of the value of exchange coupling constant at the interface on H eb at different temperatures. The effect of interfacial coupling on the magnetic ordering of models of coupled bilayers was studied using MC simulations by Tsai et al 230 231 and Alonso et al, 232 and by Finazzi 233 in a micromagnetic approach.…”

Ground state configurations in antiferromagnetic ultrathin films with dipolar anisotropy

“…The addition of a Zeeman term depends on whether the system is submitted to an applied field or not. Thus, for instance, Monte Carlo (MC) calculations are carried out with a Hamiltonian that includes a planar anisotropy, along with a perpendicular anisotropy, in the magnetocrystalline term for ultrathin films with simple cubic (sc) crystals grown in the [001] direction [7]. Different relative strengths of the included contributions define distinct antiferromagnetic phases with the XY-plane (ip) or Z-axis (op) magnetization.…”