Mixed state in antiferromagnetic chromium

The magnetic torque and magnetostriction of a single Q sample of chromium, Q being the wavevector of the spin density wave, have been measured in the neighbourhood of the spin flip temperature in magnetic fields up to 107 kOe. The experimental results are found to be inconsistent both with a uniaxial-antiferromagnet model and with an intermediate state model, but a mixed state model explains most features of the behaviour. In this model the transverse spin density wave domains produced below the spin flip temperature by a field close to Q are stabilised by a negative wall energy at the boundary with the longitudinal spin density wave domains.