ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report neutron diffraction studies of magnetic correlations in MBE-grown (111) EuTe/PbTe multilayers. Bulk EuTe is a type-II fcc antiferromagnet. This structure consists of ferromagnetic (FM) sheets of spins on (111)-type planes which are coupled antiferromagnetically to one another. In EuTe/PbTe the lattice mismatch strain selects an arrangement of the FM sheets parallel to the multilayer plane. Thus, in the case of an odd number of EuTe monlayers, there should be a nonzero magnetic moment—in other words, such superlattices are expected to behave as ferrimagnets, not anitferromagnets. This has been confirmed by recent SQUID studies. As suggested by the above model, the dipolar fields arising from the lack of total moment compensation may introduce interlayer magnetic coupling, even though in this system there are no carriers that can transfer magnetic interactions across the nonmagnetic spacers through the RKKY mechanism, which is usually the case in coupled magnetic multilayered systems. Our experiments have indeed revealed clear magnetic superlattice peak patterns in several samples. The results of measurements in high external fields (up to 6 T) bring further support for the dipolar nature of the observed interlayer coupling. However, in some contrast to the expected scenario, the most pronounced coupling effects were seen in the case of an even number of monolayers. Possible explanations of this fact (e.g., higher-order terms in dipolar fields, or structural imperfections) are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.358309
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