Low-energy excitations probed by 51V NMR in the multiferroic Ni3V208

We present results of the single-crystal 51V NMR measurements in the multiferroic compound Ni3V208. 51V Knight shifts in a magnetic field parallel to the b axis follow the Curie-Weiss law with the Weiss temperature, −9.5 K, comparable to the onset temperature of long-range magnetic order, THI = 9.4 K, where the high-temperature incommensurate magnetic order takes place. Non-linearity in the Knight shift vs magnetic susceptibility plot suggests the significant Dzyaloshinsky-Moriya interaction above THI. Despite three successive magnetic transitions below THI, the 51V nuclear spin-lattice relaxation rate measured along the b axis shows a critical slowing down only at THI.