Thin film magnetoelectric composites near spin reorientation transition

We report the use of a magnetic instability of the spin reorientation transition type to enhance the magnetoelectric sensitivity in magnetostrictive-piezoelectric structures. We present the theoretical study of a clamped beam resonant actuator composed of a piezoelectric element on a passive substrate actuated by a magnetostrictive nanostructured layer. The experiments were made on a polished 150 mm thick 18 x 3 mm(2) lead zirconate titanate (PZT) plate glued to a 50 mm thick silicon plate and coated with a giant magnetostrictive nanostructured Nx(TbCo2 5nm/FeCo5nm) layer. A second set of experiments was done with magnetostrictive layer deposited on PZT plate. Finally, a film/film structure using magnetostrictive and aluminium nitride films on silicon substrate was realized, and showed ME amplitudes reaching 30 V Oe(-1) cm(-1). Results agree with analytical theory. (C) 2009 Elsevier B.V. All rights reserved.