Tuning structural properties, morphology and magnetic characteristics of nanostructured Ni-Co-Fe/ITO ternary alloys by galvanostatic pretreatment process

Abstract

In this research, the structural properties, surface morphology, and magnetic characteristics of nanostructured ternary ferromagnetic alloys grown by a cost-effective and effortless two-step electrochemical deposition method on indium tin oxide (ITO) substrates with and without a galvanostatic pretreatment process (GPP) were examined. The GPP was applied at various pretreatment current densities (PCDs) such as -10, -20, and - 30 mA/cm² . The effect of the PCD on the Ni, Co, and Fe contents is found to be insignificant and all resultant Ni-Co-Fe thin films show an abnormal co-deposition. The films have nano-sized crystallites ranging from 17.3 to 19.6 nm and showed a face-centered cubic structure with the [111] preferential growth. Compared to the non-GPP applied Ni-Co-Fe film, growing the ternary Ni-Co-Fe film on ITO at the PCD of -30 mA/cm² causes an improvement in the crystal quality and a reduction in the particle size from 150 ± 50 to 70 ± 20 nm. A decrement in the surface roughness and coercivity was also achieved by applying the GPP at the PCD of -30 mA/cm² , but the opposite is true for the GPP performed at the PCD of -10 mA/cm² . The GPP has an effect on the magnetic Squareness Ratio (SQR), but the influence of the PCD on the SQR parameter is negligible. The obtained findings reveal that the properties of the Ni-Co-Fe/ITO ternary alloys can be tuned through the GPP applied in various PCDs. HIGHLIGHTS: • The effect of the PCD on the Ni, Co, and Fe contents is found to be insignificant. • The films have nano-sized crystallites and showed a face-centered cubic structure with the [111] preferential growth. • The analysis reveals that the GPP changes the crystal quality, H_c parameter, surface roughness, and particle size of the films. • The GPP has an effect on the magnetic squareness ratio (SQR), but the influence of the PCD on the SQR parameter is negligible. • The films had nano-sized crystallites ranging from 17.3 to 19.6 nm. • The films were ferromagnetic, and the H_c and SQR parameters of the films ranged from 30.2 to 42.7 Oe and from 8.8% to 19.6%.

Keywords: Ni-Co-Fe ternary alloys; atomic force microscopy; crystal quality; electrochemical deposition method; galvanostatic pretreatment process; indium tin oxide; magnetic properties; scanning electron microscopy; surface performance.