Magnetic and structural properties of Ni–Mn–Ga Heusler-type microwires

We report on the fabrication, and the magnetic and structural properties of novel glass-coated Ni50.95Mn25.45Ga23.6 microwires with a metallic core diameter of 44 μm and a total diameter of 82 μm prepared by the Taylor–Ulitovsky method. These annealed microwires showed ferromagnetic behaviour with a well-defined easy axis that corresponds to the axis of the wire. X-ray diffraction confirmed a tetragonal martensitic structure with a lattice parameters a = 3.75 Å and c = 6.78 Å. The Curie temperature was estimated to be ∼315 K. The maximum entropy change at the magnetic transition was −0.7 J kg−1 K−1.