INVESTIGATION OF FACE-CENTERED-CUBIC FE THIN-FILMS USING WEDGED SAMPLES

The structural and magnetic properties of metastable face-centered-cub ic (fcc) Fe thin films on fee Co(100) substrate were studied using wed ged samples, fee Co(100) was chosen for the substrate because it is st ructurally very similar to Cu(100) but is ferromagnetic at room temper ature. Reflection high energy electron diffraction and low energy elec tron diffraction characterizations confirm that epitaxially grown (MBE ) Fe on Co(100) is structurally very similar to Fe on Cu(100): face-ce ntered-tetragonal (fct) for d(Fe)< 6 ML, fee for 6 ML < d(Fe) < 11 ML, bcc for d(Fe) > 11 ML. In situ surface magneto-optic Ken effect measu rements show that at room temperature the fct and bcc regions are ferr omagnetic, while the fee region is nonferromagnetic with some magnetic live layers. All magnetizations are in-plane. Oxygen absorption exper iments suggest that these live layers are at the Fe/Co interface. Low temperature growth Fe/Co(100) shows a Ken signal that increases linear ly with d(Fe) and suggests that the magnetic moments for fee Fe and bc c Fe are the same. To further study the magnetic properties of the non ferromagnetic ''fcc'' phase, we used metastable fee Fe as a spacer lay er between two Co layers. The Co/fcc Fe/Co on Cu(100) sandwiches exhib it ferromagnetic coupling, strong antiferromagnetic coupling (AFC) and weak AFC. An oscillation in the strong AFC was found by artificially lengthening the thickness range of the nonferromagnetic fee phase. (C) 1996 American Vacuum Society.