Effect of structural disorder on the electronic and phononic properties of Hf doped BaTiO3

Sati, Aanchal; Mishra, Vikash; Kumar, Anil; Warshi, M. Kamal; Sagdeo, Archna; Kumar, Rajesh; Sagdeo, Pankaj R.

doi:10.1007/s10854-019-01281-5

Cited by 42 publications

(37 citation statements)

References 87 publications

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“…[17] The optical properties have been studied by optical absorption spectroscopy (OAS) experiments in the wavelength range 200-800 nm. [14,15,29,30] Valence band spectroscopy measurements were carried out to investigate the effect of Cr substitution on the density of states (DOS) near the Fermi level. Excitation of monochromatic He-1 line from SPECS (UVS 300) source has been used to study the valence band of the prepared samples at the experimental station of angle-resolved photoelectron spectroscopy beamline BL-10 with a SPECS Phoibos 150 electron energy analyser with base vacuum~7 × 10 −11 mbar at Indus-2 synchrotron source.…”

Section: Methodsmentioning

confidence: 99%

“…Raman spectroscopy (RS) is a widely used fast, effective, and non‐destructive spectroscopic tool to explore the vibrational properties. [ 14–16 ] It is now well established that RS is one of the versatile technique not only to investigate the crystal structure but also to study the orbital mediated CT mechanism in doped rare earth ortho‐ferrites. [ 3,17,18 ]…”

Section: Introductionmentioning

confidence: 99%

“…[11,13] Raman spectroscopy (RS) is a widely used fast, effective, and non-destructive spectroscopic tool to explore the vibrational properties. [14][15][16] It is now well established that RS is one of the versatile technique not only to investigate the crystal structure but also to study the orbital mediated CT mechanism in doped rare earth orthoferrites. [3,17,18] It is well known that the atomic arrangement with orthorhombic symmetry decompose into Raman active (7A g + 7B 1g + 5 B 2g + 5B 3g ), eight inactive modes (8 A u ), three acoustic translational modes (1 B 1u + 1 B 2u + 1 B 3u ), and 25 IR-active modes (7 B 1u + 9 B 2u + 9 B 3u ).…”

Section: Introductionmentioning

confidence: 99%

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Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Kumar

Umrao

Sagdeo

2020

J Raman Spectroscopy

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We report the possible origin of orbital facilitated new Raman mode in orthorhombic perovskite PrFe1‐xCrxO3. For this purpose, resonance and power‐dependent Raman spectroscopy measurements have been carried out to understand the origin of local oxygen breathing mode in the mixed Fe–Cr orthorhombic perovskites through the orbital mediated charge transfer mechanism. It has been observed that multi‐phonon scattering is highly sensitive to the presence of mixed Fe–Cr ions and is absent in pure iso‐structural vacuum annealed PrFeO3. The Raman spectroscopy results infer a scaling in the intensity of octahedral breathing Raman mode around 660 cm−1, which is attributed to the lattice rearrangement due to the transfer of an electron from Cr3+(d3) to Fe3+(d5) and results to d2–d6 (Cr4+–O−2–Fe2+) configuration. The interactions of d2–d6 configuration are different from d3–d5 configuration, which leads to the octahedral lattice rearrangement and activates the new Raman mode. The charge transfer phenomenon is supported through first‐principle calculations and valence band spectroscopy.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Kumar

Umrao

Sagdeo

2020

J Raman Spectroscopy

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“…Raman spectroscopy is a nondestructive and versatile atomic scale probe to characterize the vibrational properties and provides in-depth measurement information related to the electron lattice coupling (EPC) and structural distortion in the oxide materials. ,,, PrFeO3 has an orthorhombic distorted structure having 24 Raman-active modes which decompose into (7Ag + 7B1g+ 5 B2g+ 5B3g), 25 infrared-active modes (7 B1u + 9 B2u + 9 B3u), 8 inactive modes (8 Au), and 3 acoustic translational modes (1 B1u + 1 B2u + 1 B3u) . The detailed study on the Raman mode assignment had already been carried out in our earlier reports on the same samples .…”

Section: Resultsmentioning

confidence: 99%

“…The XAS beam size used for Fe L-edge, Cr L-edge, and O K-edge measurements was ∼500 μm × 500 μm. The optical properties of the prepared series of samples have been investigated using an Agilent Carry 60 UV–vis spectrophotometer, − and the variation of the optical band gap as a function of Cr content is tabulated in Table . The vibrational properties of the system have been investigated using a LABRAM HR dispersive spectrometer equipped with a 633 nm excitation laser source having a CCD detector in the backscattered mode. ,− …”

Section: Methodsmentioning

confidence: 99%

Investigations on the Electronic Structure of the Strongly Correlated Electron System Cr-Doped PrFeO₃

et al. 2021

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Here, we have demonstrated X-ray absorption spectroscopy, synchrotron X-ray diffraction, and Raman scattering studies on Cr-doped PrFeO3 ceramics and have proposed a possible correlation between the Goldschmidt structural tolerance factor, structural bandwidth, and eg electron bandwidth. It has been observed that these parameters scale in a similar fashion with Cr content, which infers the governance of these parameters by a common factor. Soft XAS experiments performed at Fe L-edge and O K-edge suggest the enhancement in overlapping between Fe 3d–O 2p orbitals, which results in an increase in the values of the eg electron bandwidth. Furthermore, with the help of strong experimental and theoretical evidence on the same samples, a mechanism in terms of orbital-facilitated charge transfer from Cr3+–O2––Fe3+ has been proposed. The importance of this mechanism lies in the fact that the Raman mode generated around 660 cm–1 may provide qualitative information about Δ, which is completely a new approach toward the information related to Δ. Thus, with the help of different experimental techniques, a correlation between the Goldschmidt structural tolerance factor, structural bandwidth, and eg electron bandwidth has been established.

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Halide tuning in derivative organic–inorganic perovskites, MAPb(Br1-xClx)3 (x = 0–1): exploring structural, optical and vibrational characteristics

Dutt,

Trivedi,

Rambadey

et al. 2024

J Mater Sci

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Organic–inorganic metal halide perovskites (OIMHP’s), particularly CH3NH3PbX3 (X = I, Br, Cl) and their derivatives shows favorable properties for energy harvesting such as high absorption coefficients, adjustable band gaps, and low charge recombination rate. The structure and hence nature of bonding between different atoms of these perovskites is known to affect their properties significantly. Tuning of band gap can be achieved in these systems with the help of compositional variation. These systems are studied extensively in the single halide compositions (MAPbI3, MAPbBr3 and MAPbCl3); while, their derivatives seem to have gained less attention though being important for various applications. So, in this work, halide tuning is achieved in derivative perovskite, MAPb(Br1-xClx)3 (x = 0 to 1) and further studied for structural and optical properties along with vibrational properties using X-ray diffraction (XRD), diffuse reflectance spectroscopy, and Raman spectroscopy techniques, respectively. A decrease in the lattice parameter is observed as the Chlorine content increases in the MAPb(Br1-xClx)3 (x = 0 to 1) perovskite. The substitution of Chlorine with Bromine also results in significant increase in the band gap value. In contrast to previous reports, it was clearly observed that the Urbach energy strongly depends on the composition. For the first time, appearance of two features for torsional mode of methylammonium (MA) is discussed even at room temperature, indicative of disorder. It is observed that although the band gap tuning is achieved with the help of halide mixing (Br and Cl), it is also found to introduce disorder in the intermediate compositions; while, the stability increases toward Chlorine compositions. Interestingly, the information of disorder is found to be contained in both the global as well as local measurements which opens up new pathways for studying these materials. This study will lay down a pathway for better understanding of key properties of these hybrid mix halide perovskites which are promising material for futuristic energy applications.

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Effect of structural disorder on the electronic and phononic properties of Hf doped BaTiO3

Cited by 42 publications

References 87 publications

Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Investigations on the Electronic Structure of the Strongly Correlated Electron System Cr-Doped PrFeO₃

Halide tuning in derivative organic–inorganic perovskites, MAPb(Br1-xClx)3 (x = 0–1): exploring structural, optical and vibrational characteristics

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Effect of structural disorder on the electronic and phononic properties of Hf doped BaTiO3

Cited by 42 publications

References 87 publications

Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO3: A brief Raman study

Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO3: A brief Raman study

Investigations on the Electronic Structure of the Strongly Correlated Electron System Cr-Doped PrFeO3

Halide tuning in derivative organic–inorganic perovskites, MAPb(Br1-xClx)3 (x = 0–1): exploring structural, optical and vibrational characteristics

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Product

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Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Orbital facilitated charge transfer originated phonon mode in Cr‐substituted PrFeO₃: A brief Raman study

Investigations on the Electronic Structure of the Strongly Correlated Electron System Cr-Doped PrFeO₃