Polymorphism and Properties of Bi2WO6 and Bi2MoO6

Yanovskiǐ, V. K.; Воронкова, В. И.

doi:10.1002/pssa.2210930106

Cited by 63 publications

(86 citation statements)

References 23 publications

(3 reference statements)

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“…[5] In addition to the paraelectric-ferroelectric phase transition, it has been suggested by several authors that a second structural phase transition exists, at a temperature of about 660 8C. [6,7] Watanabe [6] used dilatometric and differential thermal analysis (DTA) measurements to suggest an intermediate phase change with very small enthalpy and change in dimensionality of the crystals; Yanovskii and Voronkova [7] quantified this somewhat further by carrying out a high-temperature powder XRD study and suggested a second polar orthorhombic phase at approximately 690 8C < T < 960 8C. Knight has studied this intermediate temperature (IT) phase in detail using PND, [8] and established unequivocally that the material in this temperature regime adopts the orthorhombic B2cb space group, and retains the essential Aurivillius structure, albeit losing one "tilt" mode of the perovskite-like octahedral layer.…”

Section: Introductionmentioning

confidence: 99%

Unusual High‐Temperature Structural Behaviour in Ferroelectric Bi₂WO₆

McDowell

Knight

Lightfoot

2006

Chemistry A European J

157

135

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The crystal structure of Aurivillius phase ferroelectric Bi2WO6 has been studied in detail as a function of temperature by using high-resolution powder neutron diffraction. In agreement with an earlier study, a transition from space group P2(1)ab to B2cb occurs at about 660 degrees C. This transition corresponds to the loss of one octahedral tilt mode within the perovskite-like WO4 layer of the structure. A second, reconstructive, phase transition occurs around 960 degrees C, corresponding to the ferroelectric Curie point; in contrast to previous suggestions, the structure of this high-temperature phase contains layers of stoichiometry WO4, with WO6 octahedra sharing edges and corners, and with the fluorite-like Bi2O2 layers remaining essentially unchanged. This structure is closely related to that of the ambient temperature phase of lanthanide-doped derivatives, for example, Bi0.7Yb1.3WO6 recently reported. This phase-transition behaviour is in stark contrast to that of other members of the Aurivillius family, such as SrBi2Ta2O9 and Bi4Ti3O12, which retain the archetypal Aurivillius connectivity at all temperatures.

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Section: Introductionmentioning

confidence: 99%

Unusual High‐Temperature Structural Behaviour in Ferroelectric Bi₂WO₆

McDowell

Knight

Lightfoot

2006

Chemistry A European J

157

135

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“…Single crystals of Mn-doped BW (Mn-BW) were also grown. Optical microscope observations confirmed that the crystals without twin boundaries such as 90 domain walls were obtained, because the soaking temperature was set below the Curie point (940 C) [13,72,108,118]. Inductively coupled plasma (ICP) emission spectroscopy analysis showed the composition of Mn-BW crystals was Bi 2 W 0.…”

Section: Crystal Growth and Measurementsmentioning

confidence: 84%

“…The polarization switching was achieved only after J was reduced to a sufficiently low value of the order of 10 À8 A/cm 2 by Mn substitution. Figure 14.4 shows the s along the a axis as a function of oxygen partial pressure (Po 2 ) at 500 and 600 C. The s of BW and Mn-BW was independent of Po 2 from 400 to 800 C. These results reveal that in-plane electrical conduction at high temperatures in the BW system is governed by oxide-ion conduction through V O [13,104,118], as observed also for paraelectric Bi 4 Ti 3 O 12 along the a axis [4,39]. Mn-BW exhibited Fig.…”

Section: Defect Control and Propertiesmentioning

confidence: 94%

“…Bi 2 WO 6 (BW) has been regarded as a potential candidate for ferroelectric and piezoelectric materials because of its high Curie temperature of 940 C and high electromechanical coupling coefficient [26,38,72,118]. Especially, BW has the largest P s estimated from the structural data based on ionic model among BLSFs [90,113].…”

Section: ¼ 1: Bi 2 Wo 6 -Based Single Crystalsmentioning

confidence: 99%

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Defect Control and Properties in Bismuth Layer Structured Ferroelectric Single Crystals

Noguchi

Miyayama

2011

Lead-Free Piezoelectrics

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The static and dynamic behaviors of ferroelectric domains are the underlying basis of various functional properties of ferroelectric materials, such as dielectricity, piezoelectricity, ferroelectricity, and electro-optic and acoustic-optic effects. Since the performance of ferroelectric devices is governed by these behaviors, various techniques for enhancing device performance have been widely investigated with the aim of controlling ferroelectric domains [19,20,88,109]. Such control, however, is often prevented not only by a large leakage current but also by undesirable behaviors such as domain clamping [16,73,95], fatigue [17,98], aging [63,68], imprinting [110], and depoling [98]. Ferroelectric devices thus suffer from degraded polarization and poor reliability due to insufficient control over ferroelectric domains. It is considered that the poor polarization properties, fatigue, and aging, etc. are governed by the interaction between defects and ferroelectric domains.Bismuth layer-structured ferroelectrics (BLSFs) have attracted much attention because of their high Curie temperature (T C ) and larger spontaneous polarization (P s ). The relation between crystal structure and ferroelectric properties of BLSFs has been widely investigated because of their anisotropy of ferroelectric polarization [10,22,113]. In the crystal structure of BLSFs, perovskite layers (A mÀ1 B m O 3m+1 ) are sandwiched between Bi 2 O 2 layers, where m is the number of BO 6 octahedral layers with A-site cations in the perovskite layers, as shown in Fig. 14

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“…At higher temperatures it has transformed into tetragonal nonpolar phase (4/mmm) [5]. The phase transitions of BW and BM have been studied for more than four decades now, but the number of transitions and their detailed nature are not yet fully clear [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%