Scaling Axes and the Spin-Flop Bicritical Phase Boundaries

The orientation of the scaling axes at nonsymmetric critical and multicritical points is discussed. Although nonuniversal, the orientations at a spin-flop bicritical point may be found to leading order in the magnetic anisotropy and in ε=4-d (where d is the dimensionality). The resulting geometry of the antiferromagnetic phase boundaries accords well with new experimental data.