We report the first observation of spin tunneling effect on the ZnNi-ferrite encapsulated Ni-Fe microspheres, which is measured by the impedance spectra using a network analyzer. The field dependence of impedance of the composites has shown a typical behavior of magneto-tunneling effect, with a maximum magneto-impedance ratio of about 2.35%, at a frequency of 100 kHz and at the room temperature. The temperature dependence of the magnetoimpedance and dielectric modulus has been investigated to explore the origin for tunneling mechanism. Implications for magnetic sensing are discussed.
ASJC Scopus subject areas