Effects of substituting Mn with Ga in the multiferroic properties of TbMnO3

Abstract

We here report the characterization of the crystal structure, magnetic properties and specific heat of TbMn1-xGaxO3 samples (x≤0.4). Metamagnetic transition was observed at low temperature for all compounds. Heat capacity was used to test the effect of Ga on the different phase transitions. The substitution of Ga for Mn is detrimental for the antiferromagnetic ordering of Mn3+ showing a continuous decrease of TN with increasing the Ga content. This substitution also decreases the entropy content of the transition due to the ordering of Tb 3+moments. The anomaly ascribed to the ferroelectric transition is absent at zero field in Ga-based samples but it reappears at high magnetic fields in compounds with low Ga content. This result suggests that an external magnetic field induces ferroelectricity in the doped compounds. © 2010 IOP Publishing Ltd.