Lattice Anisotropy in Antiferromagnetic Chromium

Thermal-expansion and magnetostriction measurements on single-Q, single-crystal chromium give the lattice parameter ratios in the transverse spin-density-wave phase, through the spin-flip transition, and in the longitudinal spin-density-wave phase. The spin-flip transition is found to be accompanied by anisotropic discontinuities in length, resulting in a net volume dilatation of 1.4×10−6 with decreasing temperature. The Q direction is found to be the longest axis at 300°K and to bcome the shortest axis below about 220°K.