Structural and multiferroic properties of Fe-doped Ba0.5Sr0.5TiO3 solids

The structural, dielectric, ferroelectric, and magnetic properties of bulk Fe-doped Ba0.5Sr0.5TiO3 (Ba0.5Sr0.5Ti1−xFexO3; BSTF) solids prepared by standard solid-state reaction were investigated. X-ray diffraction (XRD) patterns confirmed the tetragonal structure of BSTF samples. Rietveld refinements of XRD data revealed that the doping ions lead to unit cell expansion in three directions. Ferroelectric and ferromagnetic orders of the samples were observed simultaneously at room temperature. According to experimental and simulated results, two possible exchange coupling mechanisms exist in the BSTF systems, namely, nearest-site antiferromagnetic coupling and next-nearest-site ferromagnetic coupling. The two coupling mechanisms coexist in BSTF systems, leading to extraordinary ferromagnetic behavior.

► Rietveld refinements of XRD data reveal that the doping Fe ions lead to an expansion of BSTF unit cell in three directions.
► Ferroelectric and ferromagnetic orders of BSTF samples are observed simultaneously at room temperature.
► There are two possible exchange coupling mechanisms in the Fe-doped BST systems, the nearest-site antiferromagnetic coupling and the next-nearest-site ferromagnetic one.