Multiferroic Behavior in Fe doped BaTiO3 single crystals*

Single crystals of BaTiO₃ (BTO) that have been doped at the titanium site with Fe³⁺ or Mn³⁺ have previously been shown to demonstrate large and recoverable electrostrains of up to 0.8 % that is thought to be due to the alignment of defects (i.e. O^2- vacancies) with the crystallographic symmetry in the ferroelectric state when the samples are aged.[1,2] There is also the possibility that the incorporation of a magnetic ion could give rise to a magnetic signature and even potentially multiferroic coupling in these doped samples, the possibility of which has not been previously investigated. This would be of great interest as a new path to single phase multiferroic materials. In this presentation, results from magnetic and ferroelectric measurements will be presented for a 0.5% Fe doped BTO crystal. Anomalies in the magnetization at the ferroelectric-ferroelectric phase transitions, magnetocapacitance effects, and changes in the polarization with applied magnetic field confirm the existence of magnetoelectric coupling. The potential origins of this phenomenon will be discussed.
References:
1. X. Ren, Nature Mat. 3, 91-94 (2004)
2. L. X. Zhang and X. Ren, Phys. Rev. B 71, 174108 (2005)