Magnetic anisotropy influence on inverse spin hall voltage

摘要

Ferromagnetic resonance (FMR) is an effective technique for generating pure spin current in ferromagnetic (FM)/normal(NM) bilayers in which the spin pumping mechanism allows the spin angular moment to be transferred from FM layer into the adjacent NM layer via the enhancement of the damping constant. The pumped spin current transforms to charge current by the inverse spin Hall Effect (ISHE) and the associated voltage (V) could be obtained [1, 2]. In a typical NiFe/Pt bilayer system, V is measured with respect to the thickness of the NM and/or FM layer in order to extract the important physical parameters such as spin diffusion length and spin Hall angle [3, 4]. On the other hand, the relation between magnetic anisotropy of FM layer and the ISHE voltage did not receive much attention till recent days. In this work, we investigate the ISHE for a LaSrMnO (LSMO)/Pt bilayer via anisotropic FMR spin pumping. Pulsed laser deposition (PLD) technique is used to fabricate a LSMO thin film of 20nm [5] and its in-plane magnetic anisotropy is measured by inserting this film into a TE cavity with X-band excitation. The result of resonance field (H) at zero degree and with whole 360 degree rotation is shown in Fig. 1 (a) and (b) respectively. The direction of zero degree is defined as the magnetic easy axis of LSMO film.