Strain driven structural phase transformations in dysprosium doped BiFeO<sub>3</sub> ceramics

Lennox, Robert Christopher; Price, M. C.; Jamieson, William; Jura, Marek; Daoud‐Aladine, A.; Murray, Claire; Tang, Chiu C.; Arnold, Donna C.

doi:10.1039/c3tc32345e

Cited by 47 publications

(43 citation statements)

References 57 publications

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“…Furthermore, Dy 3+ displays multiple emissions in the near infrared region, which is an important feature for application in telecommunications. 6,[26][27][28][29][30][31] Great efforts have been made to obtain phosphors that can emit white light. These phosphors could be applied in light-emitting diodes (W-LEDs), which in turn could be used in numerous areas.…”

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confidence: 99%

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Freiria¹,

Ribeiro²,

Verelst³

et al. 2017

J. Braz. Chem. Soc.

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In this study, Dy 3+ -doped LaNbO 4 phosphors with a blue to white emission that can be tuned by varying the activator concentration were prepared by one-step spray pyrolysis process. According to the powder X-ray diffraction results, increasing Dy 3+ concentration favored the tetragonal phase. Slight changes were observed in the recorded Raman spectra as a function of Dy 3+ concentrations while SEM (scanning electron microscopy) micrographs presented similar profiles regardless the Dy 3+ amount. Investigation of Dy 3+ emission data in the visible range showed that rising the Dy 3+ concentration progressively shifted the emission towards the white color. All samples presented a wide excitation range from 254 to 475 nm. Keywords: spray pyrolysis, luminescence, lanthanum niobate IntroductionOver the last years, rare earth ions (RE 3+ ) have received increasing attention: solid-state materials doped with these ions can be applied in color screens, lighting, and optical devices. [1][2][3][4][5] The luminescence properties of these materials heavily depend on the structure of the electron energy levels. In RE 3+ , chemical binding affects these levels very little because orbitals 5s and 5p shield orbital 4f efficiently. 6 The f-f transitions in RE 3+ cause an array of emissions at different wavelengths, giving rise to a plethora of colors. However, f-f transitions are forbidden by the parity selection rule (Laporte rule), so they have low excitation efficiency. Excitation requires the use of a matrix and/or sensitizer that is able to absorb energy and transfer it to an emitting ion. 6,7 Lanthanum niobate (LaNbO 4 ) is a promising material for multifunctional applications. It has a band-gap of approximately 4.8 eV and emits blue and ultraviolet light when excited with ultraviolet (UV) radiation and X-rays, respectively. 8,9 Moreover, LaNbO 4 can transfer the absorbed energy to other emitting species, leading to different fluorescence emissions. 10,11 This oxide has been prepared by a number of techniques; for example, spray pyrolysis (SP), 12-14 solid-state reaction, 15-17 reactions in solution [18][19][20] and sol-gel route. 10,21 However, with an exception of our previously published work, 22 the authors were not able to finely control the size, shape, and distribution properties. Moreover, the SP process is completed in only several seconds, while other currently available methods require several hours or days to complete the process, even requiring a post annealing treatment. Briefly, SP process involves the vaporization of precursor solution followed by the drying, precipitation and decomposition in heated tubular furnace reactors. The stoichiometric ratio in the final prepared material is the same as the precursor solution, since the reaction and aggregation volume are confined in each generated micrometric droplet, which can be seen as a micro reactor. Therefore, particles synthesized by the SP process can be obtained on a laboratory or on an industrial scale. [22][23][24][25] Among the various material...

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confidence: 99%

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Freiria¹,

Ribeiro²,

Verelst³

et al. 2017

J. Braz. Chem. Soc.

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“…The presence of orthorhombic structure with Pnma phase is also consistent with the literature. 21,22 The mixed structures have been reported in various substituted/co-substituted BFO systems. 12,[23][24][25] The evolution of orthorhombic phase can be interpreted using Goldschmidt tolerance factor t, which is defined as 3þ -site (0.645 Å ) decreases the tolerance factor t according to its definition.…”

Section: Resultsmentioning

confidence: 99%

Improved magnetization and reduced leakage current in Sm and Sc co-substituted BiFeO3

Rao

Kandula

Kumar

et al. 2018

Journal of Applied Physics

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X-ray diffraction measurements revealed that an orthorhombic Pnma structure evolved with a phase fraction of 84% in the rhombohedral R3c structure of BFO upon the substitution of Sm and Sc. The changes in the intensity and the frequency of Raman modes also corroborated the structural transformation in the BSFSO compound. A decrease in grain size, reduction in porosity, and improved density were observed in the BSFSO compound. An enhanced remanent magnetization of 0.2 emu/g and coercive field of 6.2 kOe were observed, which were attributed to the structural change as well as the destruction of the spin structure with the substitution. Impedance and leakage current measurements revealed that the insulating character of BFO was improved with the substitution of Sm and Sc in BFO and was explained based on the bond enthalpy concept. The enhanced magnetic properties along with the improved insulating character of BSFSO compound will be suitable for device applications. Published by AIP Publishing.

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“…A detailed study of the helical diffuse scattering resulting from electronic textures in the candidate multiferroic YbFe 2 O 4 [60] has been performed on the Small Molecule Single-Crystal Diffraction beamline (I19) [61]. Several experiments on a variety of multiferroics, mainly to characterize the crystal structure [62][63][64] or to study structural phase transitions [65][66][67] were also performed on the Powder Diffraction beamline (I11) [68]. Magnetocaloric effects have been studied since the nineteenth century, but two breakthroughs over 100 years after their discovery sparked a renaissance in the field.…”

Section: (C) Type II Multiferroicsmentioning

confidence: 99%

The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures

Radaelli

Dhesi

2015

Phil. Trans. R. Soc. A.

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We review some of the significant contributions to the field of strongly correlated materials and complex magnets, arising from experiments performed at the Diamond Light Source (Harwell Science and Innovation Campus, Didcot, UK) during the first few years of operation (2007–2014). We provide a comprehensive overview of Diamond research on topological insulators, multiferroics, complex oxides and magnetic nanostructures. Several experiments on ultrafast dynamics, magnetic imaging, photoemission electron microscopy, soft X-ray holography and resonant magnetic hard and soft X-ray scattering are described.

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Strain driven structural phase transformations in dysprosium doped BiFeO₃ ceramics

Abstract: Chemical strain effects arising from the large size mismatch between the two A-site cations results in a lowering of the symmetry from polar R3c to a polar Cc in Bi0.95Dy0.05FeO3.

Cited by 47 publications

References 57 publications

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Improved magnetization and reduced leakage current in Sm and Sc co-substituted BiFeO3

The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures

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Strain driven structural phase transformations in dysprosium doped BiFeO3 ceramics

Abstract: Chemical strain effects arising from the large size mismatch between the two A-site cations results in a lowering of the symmetry from polar R3c to a polar Cc in Bi0.95Dy0.05FeO3.

Cited by 47 publications

References 57 publications

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Effect of Dy3+ Amount on the Structural and Luminescence Properties of LaNbO4:Dy3+ Phosphor Obtained by One-Step Spray Pyrolysis Process

Improved magnetization and reduced leakage current in Sm and Sc co-substituted BiFeO3

The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures

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Strain driven structural phase transformations in dysprosium doped BiFeO₃ ceramics