Multiferroic ceramics in BaO-Y2O3-Fe2O3-Nb2O5 system

Multiferroic ceramics in BaO-Y2O3-Fe2O3-Nb2O5 system were synthesized and their dielectric, ferroelectric and magnetic properties were evaluated. XRD results showed that the ceramic composite consists of a major phase of tetragonal tungsten bronze structured Ba2YFeNb4O15, and minor phases of monoclinic YNbO4 and hexagonal Ba3Fe2Nb6O21. Three dielectric relaxations were observed in the temperature range from 125 to 575 K. The relaxor dielectric behavior in the temperature range from 125 to 350 K was attributed to the random occupation of Fe3+ and Nb5+ ions at B site of the tungsten bronze structure. The electrode polarization and the inhomogeneous structure contributed to the high-temperature and middle-temperature dielectric relaxations, respectively. Both the ferroelectric hysteresis loop and the magnetic hysteresis loop were measured, which suggested that the synthesized ceramic composite was a promising candidate of multiferroics.