Voigt effect measurement on PLD grown NiO thin films

Abstract

AbstractNiO has great potential applications in spin valves, magnetooptical sensors, optical fibers, solar thermal absorbers, and in nonvolatile resistive random access memory devices. In our study NiMnO and NiMnLiO films have been grown on double‐side polished r‐plane sapphire substrates by pulsed laser deposition (PLD). We measured the complex Voigt angle using the polarized light from a HeCd laser, a Glan Taylor polarizer, a Hinds PEM‐100 [1] and two Lock‐Ins. The Voigt effect is a second order magnetooptic effect [2]. The polarization state of light after transmission through a sample consisting of ca. 1 μm thick, weak ferromagnetic NiO thin on purely diamagnetic r‐plane sapphire substrates has been modelled using the 4×4 matrix formalism [3] in dependence of an external magnetic field applied in‐plane, i.e. in Voigt configuration. The modelling results revealed that for the diamagnetic sapphire substrate the Voigt angle depends parabolically on the external magnetic field and that the weak ferromagnetic NiO thin films change the parabolic dependence of the Voigt angle in the range of ±0.1 T to a flat‐top shape in agreement with the experimentally determined Voigt angle (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)