  We report the low-temperature coexistence in NdFe3(BO3)4 of an incommensurate
magnetic phase with a strained commensurate magnetic phase that is primarily at
the surface of the crystal. Increasing the temperature or magnetic field
decreases the incommensurability and stabilizes the commensurate magnetic phase
above Tic ~14 K or Hic = 0.9 T. A comparison to published studies indicates the
onset of longitudinal magnetostriction and electric polarization at the
magnetic-field-induced transition, which may arise due to a basal plane
spin-flop and canting of the moments along the field direction.
