Reversible transition between perpendicular and in-plane magnetization in ultrathin films

The magnetization in ultrathin Fe layers (2.5--3.5 atomic layers) on Cu(100) reversibly switches between perpendicular (at low temperature) and in-plane magnetization (at higher temperature). The switching temperature decreases with increasing film thickness. The switching transition is attributed to the temperature dependence of the perpendicular anisotropy. The transition is accompanied by a loss of magnetization over a temperature range of 20--30 K and shows evidence for a canted-spin configuration.