Growth and Investigation of Heterostructures Based on Multiferroic BiFeO<sub>3</sub>

Vengalis, B.; Devenson, Jelena; Oginskis, A.K.; Butkutė, Renata; Maneikis, Andrius; Steikūnienė, A.; Dapkus, L.; Banys, J.; Kinka, Martynas

doi:10.12693/aphyspola.113.1095

Cited by 12 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The theoretical predictions discussed above for the conductivity of BiFeO 3 are supported by recent experimental results. In addition to some sporadic studies on BiFeO 3 that suggest p ‐type conductivity, it was shown more directly that the conductivity of Ca‐doped BiFeO 3 could be reduced by several orders of magnitude if the ceramics were sintered in an oxygen‐poor atmosphere (e.g., in N 2 ), consistent with the p ‐type conduction behavior . Thus, Ca‐doped BiFeO 3 is a p ‐type semiconductor with an activation energy ( E a ) of ~0.27–0.4 eV when sintered in oxygen or air, whereas it is an ionic conductor with E a ~0.82–1.04 eV when sintered and cooled in nitrogen (Fig.…”

Section: Dielectric Permittivity Electrical Conductivity and Defectsmentioning

confidence: 82%

BiFeO₃ Ceramics: Processing, Electrical, and Electromechanical Properties

et al. 2014

View full text Add to dashboard Cite

Dedicated to Prof. Dr. Marija Kosec, our Mari cka, who left us after a long struggle in her tenacious spirit in December 2012.Bismuth ferrite (BiFeO 3 ), a perovskite material, rich in properties and with wide functionality, has had a marked impact on the field of multiferroics, as evidenced by the hundreds of articles published annually over the past 10 years. Studies from the very early stages and particularly those on polycrystalline BiFeO 3 ceramics have been faced with difficulties in the preparation of the perovskite free of secondary phases. In this review, we begin by summarizing the major processing issues and clarifying the thermodynamic and kinetic origins of the formation and stabilization of the frequently observed secondary, nonperovskite phases, such as Bi 25 FeO 39 and Bi 2 Fe 4 O 9 . The second part then focuses on the electrical and electromechanical properties of BiFeO 3 , including the electrical conductivity, dielectric permittivity, high-field polarization, and strain response, as well as the weak-field piezoelectric properties. We attempt to establish a link between these properties and address, in particular, the macroscopic response of the ceramics under an external field in terms of the dynamic interaction between the pinning centers (e.g., charged defects) and the ferroelectric/ferroelastic domain walls. J ournalFeature BiFeO 3 ceramics. Among the most interesting are the BiFe-O 3 -PbTiO 3 (BFPT) 14,16 and BiFeO 3 -BaTiO 3 (BFBT) 15,17,18 systems, which provide both enhanced piezoelectricity and a high T C at the MPB, the latter exceeding that of Pb(Zr,Ti)O 3 (PZT) (T C~6 50°C for BFPT, T C~6 00°C for BFBT and T C~3 50°C for PZT at the MPB). In addition, a number of other BiFeO 3 -based lead-free compositions are presently the subject of intensive studies, including BiFeO 3 -REFeO 3 (RE = La, Nd, Sm, Gd, Dy), 19-21 BiFeO 3 -AETiO 3 (AE = Mg, Ca, Sr), 22-26 BiFeO 3 -Bi 0.5 K 0.5 TiO 3 27 , and BiFe-O 3 -Bi(Zn 0.5 Ti 0.5 )O 3 . 28 The piezoelectric properties of many of these ceramic systems have not yet been characterized systematically.The processing of single-phase BiFeO 3 ceramics is difficult; however, significant progress has been made recently, particularly in relation to the identification of the origins of the frequently formed nonperovskite, secondary phases. In addition, the complex relationship between processing and defects, on one hand, and the high-and weak-field electrical and electromechanical properties, on the other, has been addressed to some extent. Up to now, a lot of these new findings, in particular those relating to processing and domain-switching behavior, have not been considered sufficiently or are even ignored in the literature. Along with the aim of presenting a detailed overview of the past and recent results on BiFeO 3 ceramics, this absence or poor coverage of some important topics was one of the motivations that led us to prepare a comprehensive article, which also includes new data.The review comprises two topics on BiFeO 3 that are the most controvers...

show abstract

Section: Dielectric Permittivity Electrical Conductivity and Defectsmentioning

confidence: 82%

BiFeO₃ Ceramics: Processing, Electrical, and Electromechanical Properties

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The cation vacancies form shallow acceptor defects. Vengalis et al found that BiFeO 3 thin films prepared by RF magnetron sputtering displayed p-type semiconducting behavior [ 37 ]. Masó and West found that Ca-doped BiFeO 3 samples that had been heat-treated in O 2 at ~125 bar were p-type semiconducting [ 38 ].…”

Section: Resultsmentioning

confidence: 99%

The Effect of Niobium Doping on the Electrical Properties of 0.4(Bi0.5K0.5)TiO3-0.6BiFeO3 Lead-Free Piezoelectric Ceramics

et al. 2015

View full text Add to dashboard Cite

Ceramics in the system (Bi0.5K0.5)TiO3-BiFeO3 have good electromechanical properties and temperature stability. However, the high conductivity inherent in BiFeO3-based ceramics complicates measurement of the ferroelectric properties. In the present work, doping with niobium (Nb) is carried out to reduce the conductivity of (Bi0.5K0.5)TiO3-BiFeO3. Powders of composition 0.4(K0.5Bi0.5)Ti1−xNbxO3-0.6BiFe1−xNbxO3 (x = 0, 0.01 and 0.03) are prepared by the mixed oxide method and sintered at 1050 °C for 1 h. The effect of Nb doping on the structure is examined by X-ray diffraction. The microstructure is examined by scanning electron microscopy. The variation in relative permittivity with temperature is measured using an impedance analyzer. Ferroelectric properties are measured at room temperature using a Sawyer Tower circuit. Piezoelectric properties are measured using a d33 meter and a contact type displacement sensor. All the samples have high density, a rhombohedral unit cell and equiaxed, micron-sized grains. All the samples show relaxor-like behavior. Nb doping causes a reduction in conductivity by one to two orders of magnitude at 200 °C. The samples have narrow P-E loops reminiscent of a linear dielectric. The samples all possess bipolar butterfly S-E loops characteristic of a classic ferroelectric material. Nb doping causes a decrease in d33 and Smax/Emax.

show abstract

“…The estimated work function is 4.2 eV and its Fermi level is about 0.2 eV, which lies below the bottom of conduction band [7]. BiFeO 3 is a p-type semiconductor [33][34][35][36], whose band gap varies from 2.0 to 2.7 eV and its Fermi level lies close to its valance band. Here the band gap of BFO is calculated to be 2.07 eV according to the UV-vis DRS spectra.…”

Section: Discussion On Mechanismmentioning

confidence: 97%