Resonant enhancement of the transversal Kerr effect in the InMnAs layers

Abstract

Spectral dependences of the transversal Kerr effect (TKE) as well as of the realand imaginary parts of the permittivity of InMnAs layers were studied. Pulsedlaser ablation of Mn and InAs targets was used to form the layers on GaAs(100)substrates. Spectra of the optical constants and TKE depended substantially on layerfabrication conditions and testified to the presence of MnAs inclusions in the samples.The cross-sectional transmission electron microscopy revealed the presence ofinclusions of size 10–40 nm in the layers. At room temperature a strong resonant bandwas observed in the TKE spectra of the InMnAs layers in the energy range of0.5–2.2 eV. In this band the TKE was comparable in magnitude but opposite in signto that in the strong ferromagnetic MnAs. The resonant character of the TKEspectra was explained by excitation of surface plasmons in the MnAs nanoclustersembedded in the InMnAs semiconductor host. Modelling the TKE spectra for(InAs)1 − X:(MnAs)X nanocomposites in the effective-medium approximation (Maxwell–Garnett approximation)confirmed the assumption on the plasmon mechanism of the resonant enhancement of thetransversal Kerr effect in the InMnAs layers.