Temperature-dependent magnetic force microscopy investigation of epitaxial MnAs films on GaAs(001)

Abstract

We present variable-temperature magnetic force microscopy ͑VT-MFM͒ studies of epitaxially grown MnAs films on GaAs͑001͒. Around a critical temperature of T c ϭ40°C, the MnAs film undergoes a first order structural phase transition. Due to the strain involved, ferromagnetic ␣-MnAs and paramagnetic ␤-MnAs phases coexist as stripes along MnAs͓0001͔. The dimensions of the ␣-phase change from isolated dots at higher temperatures to well ordered stripes at lower temperatures. VT-MFM allows a close look at the evolution of domain patterns of MnAs micromagnets.

MnAs Nanocrystals Embedded in GaAs

“…Nanocomposites with ferromagnetic above room temperature MnAs nanoclusters, embedded in GaAs matrix (MnAs/GaAs), are promising candidates for this type of material (e.g. [1][2][3]). Recently, it has been reported that thermal annealing of Ga 1−x Mn x As layers leads to formation of MnAs dots (e.g.…”

Effect of Magnetic Field on the Magnetic Domain Structure of MnAs Film on GaAs(001)

“…In spite of a very large and anisotropic lattice misfit, MnAs can be epitaxially grown on GaAs(001) in good quality [2]. While the bulk MnAs shows the first-order phase transition from the ferromagnetic, hexagonal -phase to the paramagnetic, orthorhombic -phase at 313 K, -MnAs and -MnAs coexist in MnAs films epitaxially grown on GaAs(001) over a certain temperature range via the strain stabilization [3]- [7]. It is well known that the coexisting -MnAs and -MnAs phases form a self-aligned stripe structure with varying periodicity depending on the film thickness.…”

“…The temperature-dependent atomic force microscopy (AFM) and MFM show that the morphology and the structure of films are strongly correlated with the magnetic structure [3]. Low-energy electron microscopy (LEEM) and X-ray magnetic-circular-dichroism photo emission electron microscopy (XMCDPEEM), which allows a direct mapping of the in-plane magnetization, were combined to investigate the micromagnetic properties with a high lateral resolution [4].…”

Effect of magnetic field on the magnetic domain structure of MnAs film on GaAs(001)

“…In spite of a very large and anisotropic lattice misfit, MnAs can be epitaxially grown on GaAs(001) in good quality [2]. While the bulk MnAs shows the first-order phase transition from the ferromagnetic, hexagonal -phase to the paramagnetic, orthorhombic -phase at 313 K, -MnAs and -MnAs coexist in MnAs films epitaxially grown on GaAs(001) over a certain temperature range via the strain stabilization [3]- [7]. It is well known that the coexisting -MnAs and -MnAs phases form a self-aligned stripe structure with varying periodicity depending on the film thickness.…”

“…The temperature-dependent atomic force microscopy (AFM) and MFM show that the morphology and the structure of films are strongly correlated with the magnetic structure [3]. Low-energy electron microscopy (LEEM) and X-ray magnetic-circular-dichroism photo emission electron microscopy (XMCDPEEM), which allows a direct mapping of the in-plane magnetization, were combined to investigate the micromagnetic properties with a high lateral resolution [4].…”