Nuclear Magnetic Resonance Relaxation Studies of 51V in BiVO4 Single Crystal

Temperature dependences of the nuclear spin-lattice relaxation time of 51 V in BiVO 4 single crystals, undoped and doped with 1 mol% of Eu 2 O 3 , respectively, were measured in the temperature range of 140-400K. The spin-lattice relaxation times, T 1s , of both samples were divided into the long and short components. For the doped crystal, the long component of the relaxation time is much shorter than those of the undoped crystal since the paramagnetic relaxation through Eu 3+ ions was dominant. From data of the undoped BiVO 4 , it is found that the slow motion leads to the phase transition starting at 260 K, and its thermal activation energy is 0.033 eV. That is, we observed the thermally activated motion in ferroelastic which precedes the paraelastic phase transition.