Mechanochemical and chemical synthesis of multiferroic yttrium manganite

Abstract

Multiferroic materials simultaneously host at least two primary ferroic orders (ferroelectricity, ferromagnetism, or ferroelasticity) in the same phase [1]. The possibility to control ferroelectric properties via magnetic field, or the control of magnetic properties by applied electric field, makes these systems particularly interesting for high-tech application. Multiferroics can be used to manufacture multifunctional microelectronic or microwave devices, ferroelectric memory components, magnetic data storage, etc. YMnO3 is a multiferroic compound which appears in two crystal modifications, the hexagonal thermically stable form and the rhombic metastabile crystal structure. The goal of our research is to obtain multiferroic YMnO3 which would simultaneously show ferroelectric and antiferromagnetic properties. With this in mind, we compared two methods of synthesis: mechanochemical as well as chemical synthesis from citrate polymer precursors. Our results show that chemical synthesis yields powders which, apart from h-YMnO3 and o-YmnO3, also contain YMn2O5 as a secondary phase. However, conventional sintering of these powders at 1400 °C during 2 h produces h-ordered YMnO3 which is simultaneously ferroelectric as well as antiferromagnetically.