New fit of theHe3solid exchange parameters

Abstract

Using mean field theory and the high-temperature expansion we have calculated most measured quantities of magnetic solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ including the phase diagram. We have obtained a new fit using three kinds of exchange: direct nearest-neighbor exchange $J_{\mathrm{nn}}$, three-atom exchange $J_t$, and planar four-atom exchange $K_p$. We show that it is possible to fit almost all measured quantities using these three parameters with good accuracy, including the zero-temperature first-order phase-transition field, $H_1$.