Magnetic properties and large coercivity of MnxGa nanostructures

• MnxGa nanoparticles were synthesized using Molecular Beam Epitaxy.
• The tetragonal D022 structure of MnxGa (x=2.3–2.6) was found to be the dominant phase.
• The D022 phase of the MnxGa nanoparticles exhibited a large coercivity µoH=2.3 T.
• MFM showed that multiple nanoparticles contributed to a single domain.

To investigate structure–property correlations, high-coercivity MnxGa nanoparticles were synthesized by the method of sequential deposition of Ga and Mn fluxes using molecular beam epitaxy. Spontaneous nanostructuring was assisted by the use of an Au precursor and thermal annealing, and the growth properties, structure and magnetic properties were characterized. Atomic force microscopy revealed average particle dimensions of 100 nm and X-ray diffraction revealed a dominant tetragonal D022 crystal structure. Magnetic characterization at room temperature identified the presence of two magnetic phases, dominated by a high-coercivity (2.3 T) component in addition to a low-coercivity component.