A study of uranium-based multilayers: II. Magnetic properties

Autor: Springell, R, Zochowski, S W, Ward, R C C, Wells, M R, Brown, S D, Bouchenoire, L, Wilhelm, F, Langridge, S, Stirling, W G, Lander, G H
Rok vydání: 2007
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1088/0953-8984/20/21/215230
Popis: SQUID magnetometry and polarised neutron reflectivity measurements have been employed to characterise the magnetic properties of U/Fe, U/Co and U/Gd multilayers. The field dependence of the magnetisation was measured at 10K in magnetic fields from -70kOe to 70kOe. A temperature dependent study of the magnetisation evolution was undertaken for a selection of U/Gd samples. PNR was carried out in a field of 4.4kOe for U/Fe and U/Co samples (at room temperature) and for U/Gd samples (at 10K). Magnetic 'dead' layers of about 15 Angstrom were observed for U/Fe and U/Co samples, consistent with a picture of interdiffused interfaces. A large reduction in the magnetic moment, constant over a wide range of Gd layer thicknesses, was found for the U/Gd system (about 4 Bohr magnetons compared with 7.63 for the bulk metal). This could be understood on the basis of a pinning of Gd moments arising from a column-like growth mechanism of the Gd layers. A study of the effective anisotropy suggests that perpendicular magnetic anisotropy could occur in multilayers consisting of thick U and thin Gd layers. A reduction in the Curie temperature was observed as a function of Gd layer thickness, consistent with a finite-size scaling behaviour.
Comment: 18 pages, 8 figures, submitted to J. Phys.: Condens. Matter
Databáze: arXiv