High-temperature magnetostriction of magnetite and titanomagnetites

Abstract

Magnetostriction of synthetic polycrystalline magnetite and titanium-rich titanomagnetites has been measured from 25°C to their Curie temperatures. These are the first reported measurements of magnetostriction above room temperature for titanomagnetites. The thermal dependence of the polycrystalline magnetostriction constant λs(T) varies as (1-T/Tc)1.3 for titanium-rich titanomagnetites and as (1-T/Tc)0.9 for pure magnetite. The polycrystalline magnetostriction constant is well approximated by a power law equation in terms of the saturation magnetization, λs(T)∝Ms(T)n, where n=2.31 (TM0), 3.47 (TM40), 2.75 (TM60), and 2.80 (AMTM60). -from Author