Tailoring magnetic and mechanical properties of mesoporous single-phase Ni-Pt films by electrodeposition

Homogeneous mesoporous Ni-rich Ni-Pt thin films with adjustable composition have been synthesised by one-step micelle-assisted electrodeposition. The films exhibit a face-centred cubic solid solution (single phase) and their magnetic and mechanical properties can be tuned by varying the alloy composition. In particular, the Curie temperature (T_C) is shown to decrease with the Pt content and thin films with a T_C close to room temperature (i.e. Ni₅₈Pt₄₂) and below can be produced. Hysteresis loops show a decrease of saturation magnetisation (M_s) and coercivity (H_c) with decreasing Ni content. A comparison of porous and dense films reveals significantly lower saturation magnetic field strength for porous films. Concerning mechanical properties, mainly two trends can be observed: a decrease of the Young's modulus of the nanoporous films with respect to dense films by 10% in average and a progressive increase of Young's modulus with the Ni content from 4.2 GPa to 5.7 GPa in both types of films. The tunability of properties and facility of synthesis make this alloy a promising material for microelectromechanical systems (MEMS).