Effects of Ni2+ doping on magnetic and magnetoelectric properties of Y-type hexaferrite BaSrCo2Fe11AlO22

Abstract

Magnetoelectric hexaferrites are the promising candidate materials for low-consumption magnetic memory device application, due to the existence of room-temperature magnetoelectric effect and the tunable magnetic structure. In this work, we studied the Ni doping effect on a rare room-temperature multiferroic BaSrCo2Fe11AlO22. With the comprehensive study of magnetism, magnetoelectricity, and ferroelectric properties, magnetoelectric phase diagrams of BaSrCo2-xNixFe11AlO22 were established. Generally, Ni doping has two important effects on magnetic and magnetoelectric properties. One is to strengthen superexchange interactions, greatly enhancing magnetic order temperature. Another effect is to destabilize the noncollinear magnetic structure at high temperature, causing the absence of ME effect at room temperature. In addition, the converse ME effects have been studied, revealing that converse ME coupling strength become weakened with the increase in Ni concentration. Our systematic studies provide important clues for synthesizing high performance magnetoelectric hexaferrites.