Growth of (111) oriented NiFe ₂O ₄ polycrystalline thin films on Pt (111) via sol-gel processing

Polycrystalline NiFe ₂O ₄ (NFO) thin films are grown on (111) platinized Si substrates via chemical solution processing. θ-2θ x-ray diffraction, x-ray pole figures and electron diffraction indicate that the NFO has a high degree of 111 uniaxial texture normal to the film plane. The texturing is initiated by nucleation of (111) planes at the Pt interface and is enhanced with decreasing film thickness. As the NFO magnetic easy-axis is «111», the out-of-plane magnetization exhibits improved M _r/M _s and coercivity with respect to randomly oriented films on silicon substrates. The out-of-plane M _r/M _s ratio for (111) textured NFO thin film is improved from 30% in 150 nm-thick films to above 70% in 50 nm-thick films. The improved out-of-plane magnetic anisotropy is comparable to epitaxial NFO films of comparable thickness deposited by pulsed laser deposition and sputtering.