A Study of Uranium-based Multilayers - II. Magnetic Properties

SQUID magnetometry and polarized neutron reflectivity (PNR) measurements have been employed to characterize the magnetic properties of U/Fe, U/Co and U/Gd multilayers. The field dependence of the magnetization was measured at 10 K in magnetic fields up to 70 kOe. A reduction in the magnetic moment was found for all systems. Magnetic 'dead' layers of ~15 Å were determined for U/Fe and U/Co samples, indicative of chemically diffuse interfaces. For very thick layers, magnetic moments close to the bulk values were expected. For the U/Gd system, a large reduction in the magnetic moment, constant over a wide range of Gd layer thicknesses, was found (~4 µB compared with 7.63 µB for the bulk metal). A possible explanation for this behaviour, consistent with observations of the structure of these multilayers, is that the Gd moments are pinned at the boundaries of column-like crystallites within the Gd layers. A study of the effective anisotropy and of a finite-size scaling behaviour of the U/Gd system is also presented. PNR data were collected in a field of 4.4 kOe for U/Fe and U/Co samples (at room temperature) and for U/Gd samples (at 10 K). Model calculations of the reflectivities used inputs extracted from the structural survey carried out on these systems, combined with data from the bulk magnetization measurements.

SPRINGELL R.;  ZOCHOWKSI S. W.;  WARD R. C. C.;  WELLS M. R.;  BROWN S.;  BOUCHENOIRE L.;  WILHELM F.;  LANGRIDGE S.;  STIRLING W. G.;  LANDER G.H.; 

2008-05-05

IOP PUBLISHING LTD

JRC45246

0953-8984,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC45246,   

10.1088/0953-8984/20/21/215230,