LATTICE ANISOTROPY IN ANTIFERROMAGNETIC CHROMIUM

Thermal expansion and magnetostriction measurements on single-Q→ single-crystal chromium give the lattice parameter ratios in the orthorhombic phase below the Néel temperature and through the transition to the tetragonal phase at the spin-flip temperature, TF=122;°K. The Q→ direction is the longest axis at 300;°K and becomes the shortest axis below ∼200°K. The anisotropic discontinuities in length at TF result in a net volume dilatation, 1.4 × 10-6 with decreasing temperature. © 1969 The American Physical Society.