Spontaneous magnetostriction in antiferromagnetic ilmenite compounds

Spontaneous magnetostriction refers to a change in the volume of a solid material when it undergoes a magnetic transition. Magnetostriction has numerous technological applications, including in transducers, actuators, SONAR, and more. Recently, an unusually large and linear magnetostriction effect was observed in the antiferromagnetic compound MnTe. The linear behavior contrasts with the quadratic behavior predicted by accepted theories of magnetostriction, inviting further study. We hypothesize that short-range magnetic correlations are responsible for this behavior. To test this hypothesis, we have begun an x-ray and neutron scattering study of the antiferromagnetic ilmenite compounds MnTiO3, FeTiO3, and NiTiO3. Like MnTe, these compounds exhibit short-range magnetic correlations and spontaneous magnetostriction. I will present analysis of x-ray scattering data to characterize the magnetostriction and discuss the remaining work to be done to test our hypothesis regarding linear magnetostriction. A better understanding of spontaneous magnetostriction in antiferromagnetic materials like these will lay the groundwork for future technological applications.