Structure and magnetic property of nanometric Fe-ZnSe granular films

Nanometer granular film of ferromagnetic metal-semiconductor matrix, Fe_0.35 (ZnSe)_0.65 (volume fraction), was fabricated by the radio frequency sputtering, and the structure and magnetic property of the film have been studied. According to the dependence of low field susceptibility on temperature and the hysteresis loops at different temperatures, it was found that the nanometer-sized Fe particles in granular films showed the magnetic relaxation effect at definite temperature. The magnetic property of granular film changes from super-paramagnetic into ferromagnetic at the blocking temperature T_B = 50 K. Above T_B the Mg (T) of the granular films follows the Bloch's spin wave T^3/2 law. The causes of increase of the spin wave constant are explored and analyzed.