Spinel ferrite films by a novel solution process for high frequency applications

Highly crystalline spinel MnZn-ferrite films applicable in high frequency devices were prepared by a simple and novel wet-chemical process. A stable precursor solution was prepared using dextran as complexing agent. Thus prepared solution was sprayed onto substrates fixed on a rotating table. The reaction temperature of 90 °C and slightly alkaline pH of the precursor solution were suitable for the formation of MnZn-ferrite films. The as-prepared films were highly crystalline and hence post-annealing was not required to obtain spontaneous magnetization. The real and imaginary permeability (μ′ and μ″), and the resonance frequency (fr) could be tuned by varying the Zn concentration in the film. Since the film exhibits large magnetic loss, they can be used as electromagnetic compatible (EMC) materials, by which conducted noise in mobile computer and cellular phone can be suppressed effectively.