Magnetic anisotropy and microstructure of nanocrystalline soft iron-based thin films

Abstract

The author has fabricated series of FeN and FeTaN single layers, FeTaN/TaN/FeTaN sandwiches and [FeTaN/TaN]n multilayers and studied their magnetic anisotropy, microstructure and magneto-resistance. The evolution of in-plane uniaxial anisotropy in the Fe(N) thin films is attributed to the directional order mechanism. The 90o easy axis switching of FeTaN thin films might be due to the changing of stress distribution. The evolution of the in-plane anisotropy with the changing of tTaN in the FeTaN/TaN/FeTaN sandwiches is ascribed to three possible mechanisms: interlayer magnetic coupling, stress and interface roughness. With increasing tTaN, the values of coercivity, grain size and amplitude of maximum MR of the [FeTaN/TaN]n multilayers all decrease first and then increase. This trend is associated with an evolution of in-plane magnetic anisotropy, and we attribute the phenomena to the interlayer coupling effect of FeTaN films as a function of t(TaN).