Regular articleFabrication and magnetization reversal of L10 FeMnPt dots surrounded by paramagnetic A1 phase formed by ion irradiation

A nanopatterning method involving a ferromagnetic (FM)-paramagnetic (PM) phase transformation caused by ion irradiation has been developed. A (Fe0.56Mn0.44)50Pt50 film with the ordered L10 structure and uniaxial magnetocrystalline anisotropy constant (Ku) of 2.1 × 106 J m− 3 was fabricated. Mn ion irradiation produced a smooth FM dot array with dot diameters of 100 nm surrounded by the PM phase, which was obtained from the induced FM-PM phase transition caused by the structural transformation from the L10 structure to the disordered A1 structure and a slight increase in the Mn content. The magnetization reversal process was studied by investigating the angle dependence of the dot reversal field.

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