Roger Ward

Abstract:

Arrays of micron-sized stripes of epitaxial (110) Laves phase YFe 2 films have been fabricated using a UV laser direct write system and etching process. The magnetization reversal of the stripe arrays in the sample plane is investigated by magneto-optical Kerr magnetometry. The measured MO Kerr hysteresis loops reveal that a uniaxial magnetic anisotropy can be induced in the materials by the shape of the stripes. The easy axis is found to be rigidly confined parallel to the length axis of the stripe and the hard axis is perpendicular to it. This is correlated with the induced uniaxial anisotropy which dominates the intrinsic four-fold magnetocrystalline anisotropy of the cubic Laves phase structure. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

Abstract:

U/Fe and U/Gd multilayers constitute magnetic systems, which can be used to probe the hybridisation of the 5f electrons of uranium with 3d and 4f electrons, respectively. A range of samples with varying layer thicknesses was prepared by DC sputtering in a UHV chamber. X-ray and neutron reflectivity and X-ray diffraction were used to characterise the structure of the U/Fe [A.M. Beesley, M.F. Thomas, A.D.F. Herring, R.C.C. Ward, M.R. Wells, S. Langridge, S.D. Brown, S.W. Zochowski, L. Bouchenoire, W.G. Stirling, G.H. Lander, J. Phys.: Condens. Matter 16 (2004) 8491] and U/Gd systems. A combination of polarised neutron reflectivity, SQUID magnetometry and X-ray magnetic circular dichroism have revealed an induced moment on the U site in U/Fe structures and a saturation magnetisation which increases with increasing Fe and Gd thickness. © 2006.