Band gap narrowing and magnetic properties of transition‐metal‐doped Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ lead‐free ceramics

Abstract

Transition metal (TM = Mn, Fe, Co, and Ni)‐doped Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZT) lead‐free ceramics with excellent optical and magnetic properties are synthesized via a solid‐state reaction method. The effects of TM elements on the sintering, structure, optical, and magnetic properties of BCZT ceramics are investigated in detail. Structural phase transition from the coexistence of rhombohedral and tetragonal phases to a single rhombohedral phase is observed owing to grain refinement. A narrow band gap of 1.68 eV is achieved in the Co‐doped BCZT. The optical absorption of TM‐doped BCZT is enhanced, which is ascribed to the molecular orbital rearrangement caused by lattice distortion. Moreover the magnetic behaviors of TM‐doped BCZT are observed. The Fe‐doped BCZT presents the most evident ferromagnetism, resulting from the exchange coupling interaction between the Fe3+ ions and oxygen vacancies. These results provide additional insight into the use of TM‐doped BCZT lead‐free ferroelectric ceramics for various applications.

Review on Multicatalytic Behavior of Ba0.85Ca0.15Ti0.9Zr0.1O3 Ceramic

“…When the Fe content of BCZTO ceramics rose, the band gap shifted from the UV to the visible region. The electronic states of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), which were created by Fe substitution, were used to explain the influence of Fe on the optical band gap (for BCZTO) in the stated literature [ 89 ]. Near the top of the valence band and bottom of the energy spectrum, oxygen vacancies produced extra energy states.…”