Magnetic properties of Fe films and Fe∕Si∕Fe trilayers grown on GaAs(001) and MgO(001) by ion-beam sputter epitaxy

Abstract

We grow monocrystalline Fe͑001͒ films and Fe/ Si/ Fe͑001͒ trilayers by ion-beam sputter epitaxy on GaAs͑001͒ and MgO͑001͒ substrates. Ion-beam sputtering parameters such as substrate presputtering time, substrate temperature, beam voltage, and target angle are optimized for 10-nm-thick Fe͑001͒ films with respect to epitaxial growth and magnetic properties. In situ low-energy electron diffraction patterns confirm the epitaxial and monocrystalline nature of the sputtered films, surprisingly even on untreated and thus oxidized substrates. The magneto-optical Kerr effect and ferromagnetic resonance are employed to investigate the magnetic properties, and the structural properties are characterized by atomic force microscopy and x-ray reflectivity measurements. Using the optimized set of parameters that yields the best magnetic properties for single Fe films on GaAs, we deposit epitaxial Fe/ Si/ Fe͑001͒ structures and observe antiferromagnetic interlayer exchange coupling for epitaxially sputtered Fe/ Si/ Fe͑001͒ trilayers on GaAs͑001͒. The total coupling strength reaches values of up to 2 mJ/ m 2 at a Si thickness of 15 Å.

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

“…One major driving factor behind this is the fact that MBE growth is both expensive and time-consuming; consequently making this technique unattractive for industrial application. Ion-beam sputter deposition has been used for epitaxial growth of Fe on GaAs(001), by Damm et al 82 , and on InGaAs(001) by Richomme et al 47 , and in both cases the structural quality of the films, in addition to the magnetic anisotropies, are found to be comparable to those obtained in the respective MBE-grown systems.…”