The thermal, electrical, and magnetic characterization of nickel thin films deposited via dc sputtering

Nickel thin films are widely used in microelectronic, magnetic, and sensor applications, where their functional performance is strongly influenced by morphology, oxidation state, and substrate interaction. Understanding the interplay between these factors is essential for optimizing film properties. This work presents a comprehensive characterization of the structural, electrical, thermal, and magnetic properties of nanostructured films deposited on glass substrates. The film thickness was estimated using optical interference analysis. SEM identified high-aspect-ratio nanowire-like features. The chemical composition was determined using energy-dispersive X-ray spectroscopy (EDX) analysis, and the structure was characterized by the X-ray diffraction (XRD) technique. The specific heat (SH) was measured using a Physical Property Measurement System (PPMS). Electrical characterization was performed through voltage versus current curves, and the magnetic study was conducted using Electron Paramagnetic Resonance (EPR). Electrical resistivity exhibited a nonlinear temperature dependence attributed to electron-phonon, grain boundary, and surface scattering mechanisms. EPR spectroscopy revealed the simultaneous presence of Ni²⁺ and Ni³⁺ states, which may enhance oxidation stability and influence magnetic behavior. These results demonstrate the complex interplay between nanostructure, valence states, and transport properties in thin metallic films, highlighting the value of EPR as a complementary tool in thin-film magnetism.