Study on magnetic and dielectric properties of YMnO3 ceramics

The magnetic and dielectric properties were investigated in the hexagonal YMnO3 ceramics synthesized by sol–gel method. An antiferromagnetic order about 70 K and a weak ferromagnetic order at 5 K have been detected in YMnO3 ceramics. In addition, we observed also the exchange-bias (EB) effect at low temperatures and it may originate from exchange coupling at the interface between ferromagnetic and antiferromagnetic orders for the co-existence of these two orders in some temperature region in hexagonal YMnO3. Furthermore, the dielectric measurements showed two thermally activated relaxation behaviors following the Arrhenius law in 290–430 K and above 500 K in YMnO3 ceramics and they can be explained as the dipolar effects associated with the charge carrier hopping between Mn2+ and Mn3+ and oxygen vacancy, respectively.

The YMnO3 is a well-known multiferroic material, but many basic properties of this material are still not understood. In this manuscript, we report many magnetic and dielectric results including the antiferromagnetic and ferromagnetic orders that appeared at different temperatures; the EB effect and its origin. Also we have got the dielectric behaviors at different temperatures and have discussed the origin of the dielectric behaviors. All the results mentioned above are useful in the understanding of the multiferroic property of this well-known multiferroic material.