Interlayer Coupling in EuS-Based Superlattices Deduced from Neutron Scattering Experiments

P. Sankowski a , H. Kępa b,e , P. Kacman a , A.Yu. Sipatov c , C.F. Majkrzak d and T.M. Giebultowicz e a Institute of Physics PAS and ERATO Semiconductor Spintronics Project, al. Lotników 32/46, 02-668 Warsaw, Poland b Institute of Experimental Physics, Warsaw University, Hoża 69, 00-681 Warsaw, Poland c Kharkov Polytechnic Institute, 21 Frunze St., Kharkov, Ukraine d National Institute of Standards and Technology, Gaithersburg, USA e Physics Department, Oregon State University, Corvallis, USA

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The ferromagnetic/diamagnetic semiconductor superlattices, EuS/PbS and EuS/YbSe, were studied by neutron reflectivity. In order to determine the strength of the interlayer coupling, the intensity of the first magnetic Bragg peak vs. applied external magnetic field was measured. Additionally, the in-plane anisotropy and the domain structure were studied by polarized neutron reflectivity. The dependence of the intensity of the antiferromagnetic neutron reflectivity peak vs. magnetic field was simulated using a Stoner--Wohlfarth model. To reproduce the observed spectra it was necessary to take into account the presence of fluctuations of the nonmagnetic layers thickness, by assuming a Gaussian spread of the interlayer coupling constant J. For both EuS/PbS and EuS/YbSe superlattices, the best fit was obtained for the directions of the in-plane easy axes, which agree with those determined by polarized neutron reflectivity.

DOI: 10.12693/APhysPolA.105.607 PACS numbers: 75.70.Ak, 75.25.+z, 68.65.Cd