Published online by Cambridge University Press: 21 December 2015
Mn-Ga alloys have shown promising hard magnetic properties, even though thesealloys contain no rare-earth metals. However, much work is needed before Mn-Gaalloys become viable permanent magnets for applications. One of the challengesis to enhance the remanence. One technique to improve this property is applyinga magnetic field during the heat treatment process. Magnetic annealing canpromote phase transformation of the phases with high magnetic moment. Thisresults in an increased remanence. Bulk samples of Mn-Ga alloys were made bymechanically alloying in order to create a nanostructured composite, followed byheat treatments in the presence of a 31 T magnetic field. The heat treatmenttemperatures were kept low in order to keep the refined microstructure. All thealloys exhibit hard magnetic properties at room temperature with largecoercivity. This work reports findings of magnetic field annealed Mn-Ga bulkthat exhibit high coercivities up to 19.4 kOe and increased remanence of 50%over the binary system, achieving values up to 6.9 emu/g. This is the highestcoercivity reported in bulk Mn-Ga samples.