Effect of the Magnetic Order on 3He Crystals

Solid 3 He orders magnetically into two different phases below the Néel transition depending on the magnetic field ( U2D2 or low field phase below 450 mT and CNAF or high field phase above 450 mT). We have performed measurements of the growth velocities and determined the step energies for different facets in both phases at B =0 T and B =2 T. It was found that the growth rate is much faster at B =2 T than at zero magnetic field. We conclude that the interface couples strongly to the crystal lattice at zero magnetic field while it seems to couple weakly at B =2 T. The ordering of the spins in the solid clearly affects the growth velocity of the crystals by an order of magnitude.