N. Mufti, G.R. Blake, A.A. Nugroho, T.T.M. Palstra
The influence of magnetic field on the electrical properties of Tb 1-xCaxMnO3 has been investigated by means of dielectric, polarization and neutron diffraction measurements. A field of 6T applied along the b-axis induces a crossover from ferroelectric to relaxor behavior for the x = 0.02 compound at temperatures close to the ferroelectric transition. The mechanism of this field induced crossover involves a decrease in the coherence length of the Mn-spin-spiral structure due to increasing electron hopping rates associated with double exchange. Moreover, a large negative magnetocapacitance is observed at the freezing temperature for x = 0.05, which originates from suppression of the relaxor state and thus represents a new mechanism of magnetocapacitance. © 2009 IOP Publishing Ltd.
Solid State Chemistry Laboratory, Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, 9747AG Groningen, Nijenborgh 4, Netherlands; Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132, Jalan Ganesha 10, Indonesia; Department of Physics, Universitas Negeri Malang, Malang 65145, Jalan Surabaya 6, India
