Magnetic properties of compositionally modulated Pd/Fe films

We report magnetization and⁵⁷Fe Mössbauer measurements of compositionally modulated Pd/Fe films with wavelength λ = 15 ± 1 Å and Fe layers of 1.5, 3.5, and 5.0 ± 0.5 Å thickness (films #1, #2, and #3 respectively). Magnetization measurements were made as a function of temperature (4.2 to 310 K) and of magnetic field (0.1 to 9.0 kOe). Mössbauer spectra were taken at 300 K, and also at 77 K for film #3. Enhancement of TCwas observed for film #1 and enhancement of the bulk magnetization is indicated in film #3. Magnetization measurements show in-plane anisotropy in all the films. Unlike films #1 and #2, the magnetization of film #3 increases with increasing temperature at low fields and shows a pronounced maximum. The position of the maximum shifts to lower temperature and the peak broadens appreciably with increasing field. Sample #3 also becomes magnetically harder as the temperature is lowered, indicating a complex spontaneous magnetization distribution. Mössbauer effect measurements support the existence of such a distribution.