This investigation demonstrates the magnetic properties and nanostructures of CoPt₃ wire arrays that were fabricated by electrodeposition using a porous alumina template. The X-ray absorption analysis clearly verified the occurrence of a phase transition in CoPt₃ nanowires. This phase transition significantly influences the magnetic properties and enhances coercivity and squareness. The phase transition of CoPt₃ nanowires was from a random alloy distribution to anisotropically ordered CoPt₃ (L1₂). The thermally induced phase transition of CoPt₃ nanowires to ordered L1₂ CoPt₃ through a “cluster-in-cluster” intermediate state via interdiffusion processes is revealed. The mechanism exhibited by these CoPt₃ nanowires is proposed to explain the strong correlation between their magnetic character and their atomic distribution. The research was conducted at the NSRRC beamline BL17C1.

H. M. Chen, C. F. Hsin, P. Y. Chen, R.-S. Liu, S.-F. Hu, C.-Y. Huang, J.-F. Lee, and L.-Y. Jang