Magnetization and structure of ultrathin Fe films

Received 28 July 2009; revised manuscript received 18 September 2009; published 23 November 2009 The connection between magnetization and structure of ultrathin films is studied at room temperature for the case of Fe films on W110 by inserting a 2-monolayer-thick growth-modifying Au layer between film and substrate using spin-polarized low-energy electron microscopy and low-energy electron diffraction. Ferromagnetic order with the easy axis pointing in the 11 ¯ 0 direction appears upon percolation at 1.6 monolayers. Shortly thereafter, the easy axis rotates into the 001 direction. With further increasing thickness the magnetization oscillates between the 001 and the 11 ¯ 0 direction with a maximum deviation from the 001 direction at seven monolayers where the magnetic signal has a maximum. The changes in the magnetization are associated with changes in the structure, strain, and morphology that are deduced from the diffraction patterns and which strongly influence the competition between interface anisotropy, magnetoelastic anisotropy, and dipolar surface anisotropy.