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Author |
Mallick, S.; Zhang, W.; Batuk, M.; Gibbs, A.S.; Hadermann, J.; Halasyamani, P.S.; Hayward, M.A. |
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Title |
The crystal and defect structures of polar KBiNb2O7 |
Type |
A1 Journal article |
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Year  |
2022 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
Dalton T |
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Volume |
51 |
Issue |
5 |
Pages |
1866-1873 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
KBiNb2O7 was prepared from RbBiNb2O7 by a sequence of cation exchange reactions which first convert RbBiNb2O7 to LiBiNb2O7, before KBiNb2O7 is formed by a further K-for-Li cation exchange. A combination of neutron, synchrotron X-ray and electron diffraction data reveal that KBiNb2O7 adopts a polar, layered, perovskite structure (space group A11m) in which the BiNb2O7 layers are stacked in a (0, ½, z) arrangement, with the K+ cations located in half of the available 10-coordinate interlayer cation sites. The inversion symmetry of the phase is broken by a large displacement of the Bi3+ cations parallel to the y-axis. HAADF-STEM images reveal that KBiNb2O7 exhibits frequent stacking faults which convert the (0. ½, z) layer stacking to (½, 0, z) stacking and vice versa, essentially switching the x- and y-axes of the material. By fitting the complex diffraction peak shape of the SXRD data collected from KBiNb2O7 it is estimated that each layer has approximately an ~11% chance of being defective – a high level which is attributed to the lack of cooperative NbO6 tilting in the material, which limits the lattice strain associated with each fault. |
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Wos |
000741540300001 |
Publication Date |
2022-01-05 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1477-9226 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
4 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
Experiments at the Diamond Light Source were performed as part of the Block Allocation Group award “Oxford/Warwick Solid State Chemistry BAG to probe composition-structure-property relationships in solids” (EE18786). Experiments at the ISIS pulsed neutron facility were supported by a beam time allocation from the STFC (RB 2000148). SM thanks Somerville College for an Oxford Ryniker Lloyd scholarship. PSH and WZ thank the National Science Foundation (DMR-2002319) for support. |
Approved |
Most recent IF: 4 |
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Call Number |
EMAT @ emat @c:irua:185504 |
Serial |
6951 |
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Author |
Mallick, S.; Khalsa, G.; Kaaret, J.Z.; Zhang, W.; Batuk, M.; Gibbs, A.S.; Hadermann, J.; Halasyamani, P.S.; Benedek, N.A.; Hayward, M.A. |
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Title |
The influence of the 6s² configuration of Bi³+ on the structures of A ' BiNb₂O₇ (A ' = Rb, Na, Li) layered perovskite oxides |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Journal of the Chemical Society : Dalton transactions |
Abbreviated Journal |
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Volume |
50 |
Issue |
42 |
Pages |
15359-15369 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Solid state compounds which exhibit non-centrosymmetric crystal structures are of great interest due to the physical properties they can exhibit. The 'hybrid improper' mechanism – in which two non-polar distortion modes couple to, and stabilize, a further polar distortion mode, yielding an acentric crystal structure – offers opportunities to prepare a range of novel non-centrosymmetric solids, but examples of compounds exhibiting acentric crystal structures stabilized by this mechanism are still relatively rare. Here we describe a series of bismuth-containing layered perovskite oxide phases, RbBiNb2O7, LiBiNb2O7 and NaBiNb2O7, which have structural frameworks compatible with hybrid-improper ferroelectricity, but also contain Bi3+ cations which are often observed to stabilize acentric crystal structures due to their 6s(2) electronic configurations. Neutron powder diffraction analysis reveals that RbBiNb2O7 and LiBiNb2O7 adopt polar crystal structures (space groups I2cm and B2cm respectively), compatible with stabilization by a trilinear coupling of non-polar and polar modes. The Bi3+ cations present are observed to enhance the magnitude of the polar distortions of these phases, but are not the primary driver for the acentric structure, as evidenced by the observation that replacing the Bi3+ cations with Nd3+ cations does not change the structural symmetry of the compounds. In contrast the non-centrosymmetric, but non-polar structure of NaBiNb2O7 (space group P2(1)2(1)2(1)) differs significantly from the centrosymmetric structure of NaNdNb2O7, which is attributed to a second-order Jahn-Teller distortion associated with the presence of the Bi3+ cations. |
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Wos |
000706651100001 |
Publication Date |
2021-10-05 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1477-9234 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:182584 |
Serial |
6893 |
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Author |
Parsons, T.G.; Hadermann, J.; Halasyamani, P.S.; Hayward, M.A. |
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Title |
Preparation of the noncentrosymmetric ferrimagnetic phase La0.9Ba0.1Mn0.96O2.43 by topochemical reduction |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Solid State Chemistry |
Abbreviated Journal |
J Solid State Chem |
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Volume |
287 |
Issue |
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Pages |
121356-121357 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Topochemical reduction of La0.9Ba0.1MnO3 with NaH at 225 degrees C yields the brownmillerite phase La0.9Ba0.1MnO2.5. However, reduction with CaH2 at 435 degrees C results in the formation of La0.9Ba0.1Mn0.96O2.43 via the deintercalation of both oxide anions and manganese cations from the parent perovskite phase. Electron and neutron diffraction data reveal La0.9Ba0.1Mn0.96O2.43 adopts a complex noncentrosymmetric structure, described in space group I23, confirmed by SHG measurements. Low-temperature neutron diffraction data reveal La0.9Ba0.1Mn0.96O2.43 adopts an ordered magnetic structure in which all the nearest neighbor interactions are antiferromagnetic. However, the presence of ordered manganese cation-vacancies results in a net ferrimagnetic structure with net saturated moment of 0.157(2) mu B per manganese center. |
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Wos |
000533632700029 |
Publication Date |
2020-04-05 |
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Edition |
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ISSN |
0022-4596 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.3 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
; We thank the EPSRC for funding this work and E. Suard for assisting with the collection of the neutron powder diffraction data. PSH thanks the Welch Foundation (Grant E-1457) for support. ; |
Approved |
Most recent IF: 3.3; 2020 IF: 2.299 |
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Call Number |
UA @ admin @ c:irua:169450 |
Serial |
6583 |
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Author |
Abeysinghe, D.; Smith, M.D.; Yeon, J.; Tran, T.T.; Sena, R.P.; Hadermann, J.; Halasyamani, P.S.; zur Loye, H.-C. |
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Title |
Crystal growth and structure analysis of Ce-18-W-10-O-57 : a complex oxide containing tungsten in an unusual trigonal prismatic coordination environment |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
56 |
Issue |
5 |
Pages |
2566-2575 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The noncentrosymmetric tungstate oxide, Ce18W10O57) was synthesized for the first time as high-quality single crystals via the molten chloride flux method and structurally characterized by single-crystal X-ray diffraction. The compound is a structural analogue to the previously reported La18W10O57, which crystallizes in the hexagonal space group P (6) over bar 2c. The +3 oxidation state of cerium in Ce18W10O57 was achieved via the in situ reduction of Ce(IV) to Ce(III) using Zn metal. The structure consists of both isolated and face-shared WO6 octahedra and, surprisingly, isolated WO6 trigonal prisms. A careful analysis of the packing arrangement in the structure makes it possible to explain the unusual structural architecture of Ce18W10O57, which is described in detail. The temperature-dependent magnetic susceptibility of Ce18W10O57 indicates that the cerium(III) f(1) cations do not order magnetically and exhibit simple paramagnetic behavior. The SHG efficiency of Ln(18)W(10)O(57) (Ln = La, Ce) was measured as a function of particle size, and both compounds were found to be SHG active with efficiency approximately equal to that of alpha-SiO2. |
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Place of Publication |
Easton, Pa |
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Wos |
000395847300026 |
Publication Date |
2017-02-15 |
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Edition |
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ISSN |
0020-1669 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
9 |
Open Access |
Not_Open_Access |
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Notes |
; Financial support for this work was provided by the National Science Foundation under DMR-1301757 and is gratefully acknowledged. T.T.T. and P.S.H. thank the Welch Foundation (Grant E-1457) and NSF-DMR-1503573. ; |
Approved |
Most recent IF: 4.857 |
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Call Number |
UA @ lucian @ c:irua:142449 |
Serial |
4643 |
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Author |
Retuerto, M.; Li, M.R.; Ignatov, A.; Croft, M.; Ramanujachary, K.V.; Chi, S.; Hodges, J.P.; Dachraoui, W.; Hadermann, J.; Tran, T.T.; Halasyamani, P.S.; Grams, C.P.; Hemberger, J.; Greenblatt, M.; |
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Title |
Polar and magnetic layered A-site and rock salt B-site-ordered NaLnFeWO6 (Ln = La, Nd) perovskites |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
52 |
Issue |
21 |
Pages |
12482-12491 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We have expanded the double perovskite family of materials with the unusual combination of layered order in the A sublattice and rock salt order over the B sublattice to compounds NaLaFeWO6 and NaNdFeWO6. The materials have been synthesized and studied by powder X-ray diffraction, neutron diffraction, electron diffraction, magnetic measurements, X-ray absorption spectroscopy, dielectric measurements, and second harmonic generation. At room temperature, the crystal structures of both compounds can be defined in the noncentrosymmetric monoclinic P2(1) space group resulting from the combination of ordering both in the A and B sublattices, the distortion of the cell due to tilting of the octahedra, and the displacement of certain cations. The magnetic studies show that both compounds are ordered antiferromagnetically below T-N approximate to 25 K for NaLaFeWO6 and at similar to 21 K for NaNdFeWO6. The magnetic structure of NaNdFeWO6 has been solved with a propagation vector k = (1/2 0 1/2) as an antiferromagnetic arrangement of Fe and Nd moments. Although the samples are potential multiferroics, the dielectric measurements do not show a ferroelectric response. |
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Place of Publication |
Easton, Pa |
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Wos |
000326669200035 |
Publication Date |
2013-10-18 |
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Edition |
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ISSN |
0020-1669;1520-510X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 4.857; 2013 IF: 4.794 |
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Call Number |
UA @ lucian @ c:irua:112714 |
Serial |
2656 |
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Author |
Li, M.R.; Walker, D.; Retuerto, M.; Sarkar, T.; Hadermann, J.; Stephens, P.W.; Croft, M.; Ignatov, A.; Grams, C.P.; Hemberger, J.; Nowik, I.; Halasyamani, P.S.; Tran, T.T.; Mukherjee, S.; Dasgupta, T.S.; Greenblatt, M.; |
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Title |
Polar and magnetic Mn2FeMO6 (M=Nb, Ta) with LiNbO3-type structure : high-pressure synthesis |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Angewandte Chemie: international edition in English |
Abbreviated Journal |
Angew Chem Int Edit |
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Volume |
52 |
Issue |
32 |
Pages |
8406-8410 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Place of Publication |
Weinheim |
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Wos |
000322631600044 |
Publication Date |
2013-06-27 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1433-7851; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
11.994 |
Times cited |
53 |
Open Access |
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Notes |
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Approved |
Most recent IF: 11.994; 2013 IF: 11.336 |
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Call Number |
UA @ lucian @ c:irua:110749 |
Serial |
2657 |
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