STRUCTURAL, MAGNETIC AND DIELECTRIC PROPERTIES OF Fe-DOPED BaTiO₃ SOLIDS

Abstract

The structural, ferroelectric and magnetic properties of bulk perovskite Fe -doped BaTiO 3 (BFTO) prepared by standard solid-state reaction have been investigated. X-ray diffraction (XRD) identifies the tetragonal structure of BFTO samples. Rietveld refinements of XRD data indicates that the doping ions led to ab-plane expansion and out-of-ab-plane shrinkage of the BFTO phases. X-ray photoelectron spectroscopy (XPS) measurements for the prepared samples reveals that Fe 3+ and Fe 4+ ions replaces Ti 4+ ions in the crystal lattice to form single-phase BFTO solids. The results of the temperature-dependent dielectric properties and magnetic hysteresis loops for the BFTO solids show simultaneously the ferroelectric order and ferromagnetic order at room temperature. The doping of magnetic element Fe brings about ferromagnetic order for the samples, and the measured magnetic moment for each Fe atom increases from 0.70 μB to 1.55 μB in BFTO samples. The origin of ferromagnetism of the BFTO samples should be attributed to the double exchange interactions of Fe 3+– O 2– Fe 4+ ions.

Formation of Sol–Gel In Situ Derived BTO/NZFO Composite Ceramics with Considerable Dielectric and Magnetic Properties

“…In the past few years, a large part of work has been focused on perovskite‐based ceramics, which is a typical ceramic material first discovered with excellent dielectric, ferroelectric, and piezoelectric properties . A variety of composite materials can be prepared by introducing another constituent phase into perovskite matrix to modify the comprehensive performance of these potential candidate materials for wider applications, and many factors influencing the properties of the composite system, such as type and concentration of the fillers, preparation method, grain size, microstructure etc., have been revealed in previous reports …”

Interface electronic structure in a metal/ferroelectric heterostructure under applied bias

“…The Ba 3d 5/2 spectrum has a high-binding-energy (HBE) component often attributed to under-coordinated barium at the surface for BaO termination. [21][22][23] However, for a TiO 2 -terminated surface, this is erroneous. The topmost Ba atoms are in the first layer below the surface and are fully oxygen coordinated, therefore we do not expect a surface peak due to under-coordinated Ba.…”

First-principles study of neutral defects in Fe-doped cubic barium titanate

“…The same conclusion is found in other works [52,55,56], although some discrepancy exists in the sense that our results do not predict any electron trapping from the oxygen vacancies. To our knowledge, only Guo et al [57], by photoelectron spectroscopy, and Jayanthi and Kutty [58], by electron paramagnetic resonance, have recently reported direct evidence that Fe 3 þ replaces Ti 4 þ with the creation of oxygen vacancies. Note that mode 3 is not the only one able to justify the presence of oxygen vacancies in this system, but just the simplest one.…”