Magnetic properties of thin Cr layers in multilayer systems studied through 119Sn Mossbauer probes

The magnetic properties of thin Cr layers in epitaxial [Cr(t(Cr))/Sn(2 Angstrom)] (t(Cr) = 5, 10, 20, 30, and 40 Angstrom) and [Fe(10 Angstrom)/Cr(5 Angstrom)/Sn(2 Angstrom)/Cr(5 Angstrom)] multilayers were studied through Sn-119 conversion electron Mossbauer spectroscopy. It was found that the magnetic ordering temperature of Cr in both Cr/Sn and Fe/Cr/Sn/Cr systems is much higher than the Neel temperature of bulk Cr (i.e. 311 K). It also turned out that the magnetic hyperfine fields at the Sn nuclear sites are quite different, i.e., 11-13 T for the Cr/Sn multilayers and 2 T for the Fe/Cr/Sn/Cr multilayer at 300 K, in spite of the similarity of the local crystallographic structure of the Sn probe layers. Possible magnetic structures of the Cr layers are inferred from the size and direction of the magnetic hyperfine field transferred at the Sn nuclear sites. (C) 1999 Elsevier Science B.V. All rights reserved.