|Título||Spin reorientation transition and phase diagram of ultrathin ferromagnetic films
Billoni, Orlando Vito
Pighin, Santiago Alberto
Cannas, Sergio A.
Stariolo, Daniel Adrian
Tamarit, Francisco A.
|Abstract||We show results from Monte Carlo simulations of a two-dimensional Heisenberg model for ultrathin films with perpendicular anisotropy. A complete phase diagram is obtained as a function of anisotropy and temperature, spanning a wide range of behavior. We discuss our results in relation to experimental findings in different ultrathin films. We observe and characterize a line of spin reorientation transitions. This transition from out-of-plane stripe order to in-plane ferromagnetic order presents an intermediate paramagnetic gap in a finite region of parameter space, as reported in experiments. For large anisotropies, direct transitions from a low temperature stripe phase to a paramagnetic or tetragonal phase with dominant perpendicular magnetization is observed, which is also in agreement with experiments. We also show the phase diagram for a system without exchange, i.e., with pure dipolar and anisotropy interactions. It shows a similar behavior to the ferromagnetic case with antiferromagnetic instead of stripe phases at low temperatures. A spin reorientation transition is also found in this case.
|Contido em||Physical review. B, Condensed matter and materials physics. New York. Vol. 77, no. 13 (Apr. 2008), 134417, 9p.
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|Tipo||Artigo de periódico
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