Crystal growth and properties of novel multiferroic oxide compounds

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There is an extremely increased interest to multiferroic materials such as RMn2O5 (R = rare earths) due to their promising applications as magnetoelectric materials those show strong coupling between magnetic and ferroelectric properties. The aim of this project is to grow and investigate single crystals of complex RMn2-xFexO5 and RMn2¿xCoxO5 oxides (R = Y, Tb, Ho) by two different crystal growth methods: by the conventional flux technique and the travelling solvent floating zone (TSFZ) technique. The reason of Fe and Co substitution of Mn in RMn2O5 is expected dramatic increase of temperatures (up to room temperatures), where strong magnetoelectric coupling and multiferroic behaviour appears, according to the recently obtained data on polycrystalline samples. In spite of the presence of the published results on investigation of undoped RMn2O5 crystals, no data were reported on the substituted single crystals. Therefore, the grown for the first time RMn2-xFexO5 and RMn2-xCoxO5 crystals will be studied with respect to their magnetic and ferroelectric properties, corresponding ordering temperatures and magnetoelectric effects depending on the nature of the doping element, its concentration level, valence states in the lattice and oxygen content. Crystal growth of the substituted compounds can help in understanding the fundamental problems in crystallization of doped RMn2O5 and the effects of doping element on variation of magnetoelectric properties for potential technological applications.