Electrodeposited Fe-P nanowire arrays in hard-anodic aluminum oxide templates with controllable magnetic properties by thermal annealing

Abstract

The highly ordered uniform amorphous Fe-P alloy nanowire arrays are fabricated by potentiostatic electrodeposition in hard-anodic aluminum oxide (H-AAO) templates with diameter and pore distance about 110 nm and 265 nm, respectively. The deposited Fe-P nanowire arrays gradually change from crystalline to amorphous phase as the phosphorus content in the nanowire arrays increases. The phosphorus content and nanowire growth rate are sensitive to the applied potential and sodium hypophosphite concentration in electrolyte. Subsequently, the as-deposited amorphous Fe-P alloy nanowire arrays are annealed with different temperature. And the original and annealed samples reveal different crystallographic structures and magnetic properties. The results show that both the coercivity and squareness have been improved significantly, while the magnetic anisotropy become weak with the increasing of annealing temperature, which mainly attributes to the competition of shape anisotropy, stress anisotropy and the strengthening of magnetocrystalline anisotropy.