Field-dependent competing magnetic ordering in multiferroic Ni₃V₂O₈

¹  School of Physical Sciences, Jawaharlal Nehru University - New Delhi 110067, India
²  UGC-DAE Consortium for Scientific Research, University Campus - Khandwa Road, Indore 452017, India
³  Tata Institute of Fundamental Research - Bombay 400 005, India

Corresponding author: spatnaik@mail.jnu.ac.in

Received: 22 January 2009
Accepted: 7 May 2009

Abstract

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.