Single-Ion Magnetostriction in the Iron Group Monoxides from the Strain Dependence of Electron-Paramagnetic-Resonance Spectra

Abstract

The single-ion contribution to magnetostriction in the transition metal monoxides NiO, MnO, FeO, and CoO is calculated on a very simple model and found to account for substantially all the observed magnetostriction. Exchange is included in a molecular-field approximation, and the single-ion magnetoelastic parameters $F_{\mathrm{ijkl}}={\left(\frac{\partial g_{\mathrm{kl}}}{\partial {\epsilon }_{\mathrm{ij}}}\right)}_0$ and $G_{\mathrm{ijkl}}={\left(\frac{\partial D_{\mathrm{kl}}}{\partial {\epsilon }_{\mathrm{ij}}}\right)}_0$ are obtained from data on the electron paramagnetic resonance of ${\mathrm{Ni}}^{2+}$, ${\mathrm{Mn}}^{2+}$, ${\mathrm{Fe}}^{2+}$, and ${\mathrm{Co}}^{2+}$ in MgO subject to uniaxial stress. Most of these data are available from the existing literature.