Structure evolution and magnetic properties of annealed nanoscale Gd/Ti multilayers

¹ Departamento de Electricidad y Electrónica, Universidad del País Vasco, 48080 Bilbao, Spain
² Department of Magnetism and Magnetic Nanomaterials, Ural Federal University, 620002 Ekaterinburg, Russia
³ SGIker, Servicios Generales de Investigación, Universidad del País Vasco, 48080 Bilbao, Spain

Abstract

The structure and magnetic properties were comparatively analyzed for [Gd/Ti]_n multilayers with Gd layer thickness of 1.5 to 12 nm. Multilayers were deposited by sputtering technique at room temperature and annealed for the temperatures up to 400 ºC. It was observed that the samples are highly textured in a different way depending on the Gd layer thickness and annealing temperature. It was found that the heat treatment practically does not change the Gd grain size. The lattice parameters obtained from X-ray results change significantly only for [Gd(1.5nm)/Ti]₅₀ multilayers, but their values remain higher than for the bulk Gd. The initial slope of the temperature dependence of magnetization near Curie temperature becomes steeper and Curie temperature increases upon annealing. Curie temperature variation can be understood by taking into account both relaxation of the lattice imperfections and change in lattice constants.