dc Resistivity in the Nickel and Nickel Zinc Ferrite System

TLDR

The study examined how the resistivity of nickel and nickel‑zinc ferrites varies with composition and firing temperature. Iron‑deficient nickel‑zinc ferrites exhibit higher resistivity than iron‑deficient nickel or zinc ferrites, and when fired in oxygen below 1300 °C with Ni:Zn ratios >3:7 they display a positive thermoelectric voltage, whereas other compositions or those fired above 1300 °C show negative voltage, with excess iron’s impact on resistivity contingent on zinc presence below 1300 °C.

Abstract

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 1300°C and have Ni:Zn ratios greater than 3:7, show a positive thermoelectric voltage. Other compositions or materials fired above 1300°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 1300°C.