  The geometrically frustrated magnet Ni3V2O8 undergoes a series of competing
magnetic ordering at low temperatures. Most importantly, one of the
incommensurate phases has been reported to develop a ferroelectric correlation
caused by spin frustration. Here we report an extensive thermodynamic,
dielectric and magnetic study on clean polycrystalline samples of this novel
multiferroic compound. Our low temperature specific heat data at high fields up
to 14 Tesla clearly identify the development of a new magnetic field induced
phase transition below 2 K that shows signatures of simultaneous electric
ordering. We also report temperature and field dependent dielectric constant
that enables us to quantitatively estimate the strength of magneto-electric
coupling in this improper ferroelectric material.
