Structural, Optical, and Magnetic Properties of Lead-Free Ferroelectric Bi0.5K0.5TiO3 Solid Solution with BiFeO3 Materials

Abstract

A solid solution of Bi0.5K0.5TiO3-BiFeO3 was fabricated by a sol–gel technique. The pure Bi0.5K0.5TO3 samples exhibited weak room-temperature ferromagnetism. The room-temperature ferromagnetism was observed in BiFeO3 solid solution in Bi0.5K0.5TiO3. The optical band gap of Bi0.5K0.5TiO3 was reduced from 3.22 eV to 1.39 eV with the increase in the amount of BiFeO3 solid solution. The room-temperature ferromagnetism and band gap reduction were attributed to the diffusion of BiFeO3 into Bi0.5K0.5TiO3 to form a solid solution. Our work provided a simple method of realizing room-temperature ferromagnetism in lead-free ferroelectric materials.