Table of Contents
Physics Research International
Volume 2012 (2012), Article ID 276348, 22 pages
http://dx.doi.org/10.1155/2012/276348
Review Article

Magnetic and Magnetoelectric Properties of Rare Earth Molybdates

1Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
2IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
3Departamento de Fisica de Materiales, Facultad de Quimicas, UPV/EHU, 20009 San Sebastian, Spain

Received 27 July 2011; Accepted 14 February 2012

Academic Editor: Mitsuteru Inoue

Copyright © 2012 B. K. Ponomarev and A. Zhukov. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present results on ferroelectric, magnetic, magneto-optical properties and magnetoelectric effect of rare earth molybdates (gadolinium molybdate, GMO, and terbium molybdate, TMO, and samarium molybdate, SMO), belonging to a new type of ferroelectrics predicted by Levanyuk and Sannikov. While cooling the tetragonal β-phase becomes unstable with respect to two degenerate modes of lattice vibrations. The β-β′ transition is induced by this instability. The spontaneous polarization appears as a by-product of the lattice transformation. The electric order in TMO is of antiferroelectric type. Ferroelectric and ferroelastic GMO and TMO at room temperature are paramagnets. At low temperatures GMO and TMO are antiferromagnetic with the Neel temperatures  K (GMO) and  K (TMO). TMO shows the spontaneous destruction at 40 kOe magnetic field. Temperature and field dependences of the magnetization in TMO are well described by the magnetism theory of singlets at 4.2 K ≤ T ≤ 30 K. The magnetoelectric effect in SMO, GMO and TMO, the anisotropy of magnetoelectric effect in TMO at T = (1.8–4.2) K, the Zeeman effect in TMO, the inversion of the electric polarization induced by the laser beam are discussed. The correlation between the magnetic moment of rare earth ion and the magnetoelectric effect value is predicted. The giant fluctuations of the acoustic resonance peak intensity near the Curie point are observed.