Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 9: Anisotropy/Magnetoelasticity

MA 9.1: Talk

Monday, March 26, 2007, 17:15–17:30, H22

A novel approach to induce biaxial stress on magnetic thin films and its influence on the Magnetic anisotropy — •Jorge Enrique Hamann, Senthilnathan Mohanan, and Ulrich Herr — Institute for Micro and Nanomaterials, University of Ulm, Ulm-89081, Germany

Magnetic thin films and multilayers exhibiting perpendicular anisotropy (PA) are the promising candidates for the perpendicular magnetic recording media and solid state magnetic memory. Stress induced magnetic anisotropy plays a major role for PA in magnetic-noble metal multilayer systems. The main aim of this study is to investigate the influence of biaxial stress on the magnetic anisotropy of thin films with positive and negative magnetostriction constants, namely CoFe alloy and Ni. In this study, we introduce a novel way to induce biaxial in-plane stress on to the thin films. We deposited magnetic thin films on Ta substrate and an isotropic biaxial stress is introduced in the magnetic thin films by loading the Ta substrate with H2. Films with varying biaxial tensile stress are produced by changing the H2 loading time. We measured the influence of biaxial tensile stress with the corresponding change in the out of plane hysteresis loop measurement. We observed a gradual change in the slope of M(H) curve in case of CoFe, and of saturation field in case of Ni, which correlates well with varying stresses induced in the film. We made a quantitative analysis of the data using a micromagnetic model with which we estimated the values for corresponding magnetostriction constant and crystalline anisotropy.