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Microstructures, magnetic, and dielectric properties of Ba‐doped BiFeO 3 nanoparticles synthesized via molten salt route
Author(s) -
Wu Heng,
Zhu Xinhua
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16348
Subject(s) - materials science , nanoparticle , raman spectroscopy , magnetization , multiferroics , valence (chemistry) , coercivity , doping , remanence , x ray photoelectron spectroscopy , analytical chemistry (journal) , nanotechnology , dielectric , ferroelectricity , nuclear magnetic resonance , condensed matter physics , optoelectronics , chemistry , magnetic field , physics , organic chemistry , quantum mechanics , chromatography , optics
As the paradigm of magnetoelectric multiferroic materials, BiFeO 3 (BFO) has potential applications in spintronics, memory devices, sensors, and actuators. However, its large leakage current and small magnetism at room temperature restrict its practical applications. It is demonstrated that the substitutions of Bi by alkali earth elements at A‐site of BFO can significantly reduce the leakage current and enhance the remanent magnetization of BFO. In this work, Ba‐doped BFO nanoparticles Bi 1‐ x Ba x FeO 3 ( x = 0, 0.05, 0.10, 0.15 and 0.20) were synthesized via molten salt route. X‐ray diffraction patterns revealed that with increasing the Ba‐doped content the formation of the impurity phase was depressed and the rhombohedral distortions of these nanoparticles were suppressed, as confirmed by Raman spectra. X‐ray photoelectron spectroscopy measurements reveal that the Fe element in the nanoparticles exists in the dual valence states of Fe 3+ and Fe 2+ , and two kinds of oxygen atoms (lattice oxygen atoms and the adsorbed oxygen atoms) exist in the nanoparticles. With increasing the Ba‐doped content, the content ratios of Fe 3+ to Fe 2+ ions were generally increased, whereas the oxygen vacancy concentrations were decreased. The average particle sizes of the Ba‐doped BFO nanoparticles were decreased as compared with that of nondoped BFO nanoparticles. In contrast, the room temperature magnetization of the Ba‐doped BFO nanoparticles was greatly enhanced by Ba‐substitution, as confirmed by the M ‐ H loops. At room temperature, the remanent magnetization and coercive field of the Bi 0.8 Ba 0.2 FeO 3 nanoparticles were 0.51 emu/g and 1130 Oe, respectively. Furthermore, the leakage current density was reduced by one order of magnitude at x = 0.2 and the dielectric properties are also improved by Ba‐substitution. The improvements on the remanent magnetization, leakage current density as well as dielectric properties of the Ba‐doped BFO nanoparticles make them promising candidates for spintronics and dielectric energy storages.