Liquid-Film Temperature Regulates (222) Texture and Permeability–Frequency Response in Spin-Sprayed NiZn Ferrite Thin Films

Spin-spray deposition is a low-temperature route for preparing crystalline ferrite films, but the actual liquid-film temperature has not been isolated from the nominal heater temperature. NiZn ferrite films were deposited at liquid-film temperatures of 87.6, 90.1, 92.7, and 95.0 °C. As the temperature increased, the (222) Lotgering factor fL decreased from 0.32 to 0.01, the triangular morphology weakened, and the growth rate declined. Ms remained nearly constant at 429–442 kA m−1, whereas μ′max increased from 44 to 83 and fr decreased from 465 to 260 MHz. The structural and magnetic trends are consistent with a shift from surface-confined (222)-oriented growth toward less-oriented growth and a corresponding permeability–frequency trade-off. Unlike our previous studies of substrate and oxidant effects, this work isolates the measured liquid-film temperature and establishes its quantitative relationship with texture and dynamic magnetic response. This parameter provides a practical means of selecting the operating window of spin-sprayed NiZn ferrite cores for integrated high-frequency inductors.