Magnetic spiral structures in La Fe multilayers

The magnetic properties of La/Fe multilayers were tested by magneto-optical Kerr effect and polarized neutron reflectometry. The experiments indicated that above a layer thickness t(La) = 25 Angstrom the magnetic state of the virgin sample is represented by a spiral-like arrangement of magnetization s of subsequent Fe layers, whereas each Fe layer itself is ferromagnetic. P olarized neutron reflectometry shows that the helix has predominantly one c hirality over the entire surface area of several cm(2). The magnetic spiral structure is imprinted during the growth process by rotating the sample in a small residual magnetic field. External magnetic field of 90 Oe are suff icient to erase the magnetic structure irreversibly. (C) 1999 Elsevier Scie nce B.V. All rights reserved.