Spin dynamics of buried ultra-thin magnetic layers

초록

We used Brillouin light scattering (BLS) to study spin dynamics in ultra-thin buried Fe layers grown on GaAs(001). We correlated these results with magneto-optical Kerr effect (MOKE) measurements, and with film structure obtained from reflection high energy and low energy electron diffraction (RHEED and LEED). Room temperature ferromagnetism was not present in our samples for Fe layer thicknesses below 5.9 ?L), even though we observe Fe diffraction peaks beginning at a thickness of 2.6 ?L). Our BLS data show an initial uniaxial in-plane anisotropy with easy and hard axis along the [110] and [1-10] directions, respectively, with an additional component to the anisotropy for higher Fe layer thicknesses. Our results also show that the overlayer material significantly affects the magnetic properties of the buried Fe layer. However, we observe no thickness dependence for Al and Au overlayers in the range 20-90 ?e find that annealing of room temperature deposited Fe layers to 310^oC has a significant effect on both the magnetic properties and surface structure of the Fe.