Nuclear Magnetic Resonance investigation of ferroquadrupolar order in TmVO4

TmVO4 undergoes structural phase transition from tetragonal to orthorhombic at 2.15K due to a cooperative Jahn-Teller distortion. The electronic ground state of Tm3+ is a non-Kramers doublet which is separated from the first excited state by 54 cm^-1. We have performed 51V NMR in a single crystal to investigate critical behavior below and above the ferroquadrupolar transition temperature. We observed strong divergences on the spin lattice and spin spin relaxation rates at the transition temperature, and find that the ordering temperature is suppressed with field along the c-axis.