Single crystal growth of NiZn ferrite by the Bridgeman method

Abstract

When single crystals of NiZn ferrite are grown by the Bridgeman method, at normal atmospheric pressure, Fe 3 O4is observed and results in poor magnetic characteristics. From the experimental results obtained when the oxygen partial pressure was varied from 1 to 135 kg.cm-2it is expected that an oxygen partial pressure of 500 kg.cm--2is required to obtain NiZn single crystal with Stoichiometric composition and single phase. Crystal growth at such high pressures is not convenient for production. By substituting 6 mole % of the NiO with MnO we developed a material which has stoichiometric composition and excellent magnetic characteristics when grown at the relatively low pressure of 100 kg.cm-2in an O 2 atmosphere. The magnetic characteristics are obtained as follows: μ = 95 at 50 MHz, \rho \geq 10^{3}\Omega -cm Bm=3800G and Hc=0.26Oe.