Ferromagnetic resonance measurements of GaP epilayers with embedded MnP nanoclusters grown on GaP(001)

Abstract

The relation between crystallographic texture and magnetic properties of GaP epilayers with embedded MnP nanoclusters grown by metal-organic vapor phase epitaxy is investigated with angle-dependent ferromagnetic resonance (FMR) measurements. A systematic methodology entirely based on magnetic characterization identifies all the crystallographic orientations of the MnP nanoclusters relative to the GaP matrix as well as the volume fraction of MnP in each orientation. For all 18 crystallographic orientations of the MnP nanoclusters that were determined for samples grown at 650 ◦C, the MnP c axis is oriented along GaP 〈110〉. Our approach also reveals that approximately 90% of the clusters have their b axis oriented along GaP 〈111〉, while the remaining clusters have their b axis oriented along GaP 〈100〉. In addition, FMR indicates that the ratio of the anisotropy field along the intermediate magnetic axis over that of the hard magnetic axis of the embedded MnP clusters is increased by more than 20% compared to bulk MnP. Calculations suggest that a magnetoelastic and/or a surface contribution to the magnetic anisotropy of the nanoclusters is required to explain the observed difference. The methodology presented in this work is particularly suited for semiconducting epilayers with embedded nanomagnets but could be easily applied to other similar systems.