Journal of Applied Physics -- April 15, 1996 -- Volume 79, Issue 8 pp. 4793-4795 

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Reorientational transition of the magnetic anisotropy and antiferromagnetic coupling of Co/Cr(001) superlattices

       Th. Zeidler, F. Schreiber, and H. Zabel 
       Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany 

We have measured the magnetic anisotropy of high quality Co/Cr(001) superlattices as a function of the Co thickness using the magneto-optical Kerr effect (MOKE) and a torsion magnetometer. The samples grown by
molecular beam epitaxy exhibit a reorientational transition of the easy axis from in-plane for large Co thicknesses (tCo14 Å) to out-of-plane for 10 ÅtCo14 Å and back again to the in-plane orientation for tCo
     10 Å. We provide evidence that this reorientational transition of the magnetization direction is due to a sign change of the interface anisotropy constant induced by a concomitant structural phase transition of the Co
layers from hcp to bcc with decreasing Co layer thickness. We have observed antiferromagnetic alignment of the Co layer magnetization both for in-plane and perpendicular magnetic anisotropy. The first maximum of the
antiferromagnetic interlayer interaction occurs at tCr=6 Å, which is in a good agreement with the results for Fe/Cr(001). In order to theoretically describe the spin structure of the antiferromagnetic coupled multilayers we have
performed absolute minima calculations of the angle dependent anisotropy energy. In contrast to trilayer systems we found highly asymmetric spin structures in the superlattices during the remagnetization process. ©1996
American Institute of Physics. 

PII: S0021-8979(96)51708-6] 
DOI: 10.1063/1.361870 
PACS: 75.30.Gw, 75.70.Cn, 78.20.Ls