Multiferroic properties of BiFeO3-based high entropy ceramics

Le résumé fourni par la source

The design concept of high-entropy materials is based on the stabilization of phases with improved or even novel functionalities through increased configurational entropy. This is achieved by incorporating multiple elements in nearly equimolar ratios. This strategy has already revolutionized structural materials and is now expanding to functional oxides. In this work, we applied this concept to multiferroic BiFeO 3 that has attracted significant interest due to its exceptional ferroelectric, photovoltaic, and photocatalytic properties. We prepared high-entropy ceramics with the nominal composition Bi 0.2 La 0.2 Gd 0.2 Dy 0.2 Pr 0.2 FeO 3 and examined their multiferroic properties. The ceramics possess an orthorhombic crystal structure with highly distorted oxygen octahedra, as demonstrated by local-structure determination using EXAFS. The analysis of the ferroelectric properties using piezoresponse force microscopy reveals a primary phase with relaxor or antiferroelectric character and a minor non-polar phase. Impedance analysis indicates the presence of double-ionized oxygen vacancies and high AC conductivity at elevated temperatures. The magnetic properties of the high-entropy ceramics are characterized by a combination of weak ferromagnetic and paramagnetic responses.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.