Microstructural Changes of Epitaxial Fe/MgO Layers Grown on InAs(001) Substrates

Abstract

The microstructural evolution and the effect on in-plane magnetic properties of epitaxial Fe/MgO layers grown on InAs(001) substrates have been investigated as a function of MgO growth temperature. The Fe grows three-dimensional islands with two different in-plane textures along [010] and [1 (1) over bar0] directions on the MgO layers grown below 200 degrees C in remarkable contrast to two-dimensional Fe layers on the MgO layers grown above 300 degrees C. As the MgO growth temperature increases, both tensile-strained MgO and the subsequent Fe are simultaneously relaxed, and the distribution of 45 degrees-rotated Fe lattices with [010] texture becomes dominant. The experimental results imply that the microstructural evolution of the Fe is strongly influenced by the underlying misfit strain within the MgO layers grown at different temperatures. The two different epitaxial relationships of the Fe islands lead to no magnetic anisotropy, while the Fe layer with the single epitaxial relationship of Fe[010]//MgO[1 (1) over bar0]//InAs[1 (1) over bar0] shows cubic magnetic anisotropy.