dc Resistivity in the Nickel and Nickel Zinc Ferrite System

摘要

The dependence of the resistivities of nickel and nickel zinc ferrites prepared from high purity reagents upon composition and firing temperature has been studied.It has been determined that iron deficient nickel zinc ferrites are of much higher resistivity than iron deficient nickel or zinc ferrites.The iron deficient ferrites prepared, which were fired in oxygen below 1300deg;C and have Ni:Zn ratios greater than 3:7, show a positive thermoelectric voltage. Other compositions or materials fired above 1300deg;C have a negative thermoelectric voltage.The effect of excess iron upon resistivity is dependent upon the presence or absence of zinc at temperatures below 1300deg;C.