Enhanced magnetization in erbium doped GaN thin films due to strain induced electric fields

Abstract

The ferromagnetic properties of erbium-doped GaN (GaN:Er) epilayers grown by metal-organic chemical vapor deposition were studied. It is found that the different tensile strains produced by the respective lattice mismatch for different substrates used (GaN/Al2O3, AlN/Al2O3, GaN/Si (111), and c-GaN bulk) correlate well with the observed room-temperature saturation magnetization. Under application of a magnetic field, the photoluminescence of the erbium dopant, which causes the ferromagnetism, indicates that the magnetic states of the ions are coupled to the electronic states of the host. These results hold promise for the use of strain to control the magnetic properties of GaN:Er films for spintronic applications.