Leakage current under high electric fields and magnetic properties in Co and Mn co-substituted BiFeO3 polycrystalline films

Abstract

Co and Mn co-substituted BiFeO 3 films were prepared on Pt/Ti/SiO 2 /Si(100) substrates, and the effect of co-substitution on the structural, electric, and magnetic properties of the prepared films was systematically investigated. Cross-sectional transmission electron microscopy observations showed that the films were homogeneous; moreover, no magnetic secondary phases were observed in the films. Nano-beam energy-dispersive X-ray spectroscopy, carried out at various points in the films, revealed that Co and Mn were distributed in the films. Further, the average concentration of Bi, Co, Mn, and Fe was 59, 2, 2, 37 at.%, respectively; these values were almost consistent with the nominal composition of the precursor solution used. X-ray diffraction profiles of the films showed that the (012)-d-spacing decreased and (104) and (110) peaks merged into a single peak with increasing co-substitution content. The leakage current in films under high electric fields drastically decreased upon co-substitution without any degradation of ferroelectricity; moreover, this effect was also observed for single Mn-substituted materials. Saturation magnetization of the films monotonically increased with the co-substitution content, and this increase was quantitatively identical to that in the case of single Co-substituted materials. These results indicate that Co and Mn play significant roles in determining the properties of co-substituted BiFeO 3 films.

A Comparative Analysis on the Crystalline Behavior, Topographical, Photoluminescence, and Leakage Current Characteristics of BiFeO3 Nanopowders and Thin Films

“…[5][6][7][8][9] In particular, many studies concentrated on the suppression of leakage current in BFO by adopting different synthesis techniques. [10][11][12][13][14] On perusal of available literature, significant reduction in the leakage current found to have been achieved in BFO based materials. [15][16][17][18] Most reports attribute for the decreased leakage current in BFO either due to the crystalline strain or owing to oxygen vacancies.…”

Phase transition, piezoelectric, and multiferroic properties of La(Co0.5Mn0.5)O3-modified BiFeO3-BaTiO3lead-free ceramics

“…However, for pure BiFeO 3 ceramics, there are some inherent impediments to its ferroelectricity and piezoelectricity. It is difficult to synthesize pure perovskite phase BiFeO 3 due to the formation of impurities such as Bi 2 Fe 4 O 9 [6], Bi 25 Fe 4 O 39 [7], Bi 24 FeO 40 [8], and Bi 46 Fe 2 O 72 [9]. Besides, pure BiFeO 3 usually possesses high leakage current because of the reduction of Fe 3þ -Fe 2þ during sintering [10].…”

“…Recently, it has been reported that the dielectric loss and leakage current of the BiFeO 3 -BaTiO 3 can be reduced significantly after the addition of a small amount of MnO 2 [23]. According to the previous investigations, the substitution of La 3þ [24] for Bi 3þ in BiFeO 3 can enhance the ferroelectric and magnetic properties of the ceramics while the substitution of magnetically active ions (Co 2þ , Mn 4þ ) for Fe 3þ in BiFeO 3 can tailor the ferromagnetic properties of materials [18,25]. To our knowledge, there are few reports on the ceramic with simultaneously partial substitutions of Bi 3þ (A-site) by La 3þ and Fe 3þ (B-site) by magnetic active ions Co 2þ and Mn 4þ .…”