300 citations · 1.1k across the 25 of their papers we have counts for
24 papers
Investigation of Softer Lattice Dynamics in Defect Engineered GeTe Crystals
Saptak Majumder, Pintu Singha, Sharath Kumar C. +7
The impact of Ge vacancies on the low-temperature lattice dynamics of single-crystalline GeTe was investigated through a comparative study of two off-stoichiometric samples: Ge$_{0…
Orbital fluctuations and spin-orbital-lattice coupling in Bi2Fe4O9
Aditya Prasad Roy, M. K. Chattopadhyay, Ranjan Mittal +4
Magnetic frustrations and degeneracies profoundly affect ground-state magnetic properties emerging from competing exchange interactions. Controlling such frustrations using orbital…
Wavelength-dependent anisotropic light-matter interaction in 2D ferroelectric In2Se3
Divya Jangra, Binoy Krishna De, Pragati Sharma +8
The anisotropic light-matter interactions in 2D materials have garnered significant attention for their potential to develop futuristic polarization-based optoelectronic devices, s…
Probing of Structural Phase Transitions in Barium Titanate Modified Sodium Niobate using Raman Scattering
Mrinal Jauhari, S. K. Mishra, R. Mittal +1
Raman Spectroscopic measurements are carried out to investigate the structural phase transitions as a function of composition in modified sodium niobate [(1-x) NaNbO3-xBaTiO3:NNBTx…
Negative Thermal Expansion Behaviour in MZrF6 (M=Ca, Mg, Sr): Ab-initio Lattice Dynamical Studies
M. K. Gupta, Baltej Singh, R. Mittal +1
The thermal expansion behavior of metal fluorides can be tuned by choosing appropriate metal cation. We present ab-initio lattice dynamical studies on the metal fluorides (CaZrF6,…
Phonons and Anomalous Thermal Expansion Behaviour of H2O and D2O ice Ih
M. K. Gupta, R. Mittal, Baltej Singh +4
In order to identify and quantitatively analyze the anharmonicity of phonons relevant to the anomalous thermal expansion in the Ih phase of ice, we performed neutron inelastic scat…
Lattice Dynamics and Thermal Expansion Behavior in Metal Cyanides, MCN (M=Cu, Ag, Au): Neutron Inelastic Scattering and First Principles Calculations
M. K. Gupta, Baltej Singh, R. Mittal +2
We report measurement of temperature dependence of phonon spectra in quasi one-dimensional metal cyanides MCN (M=Cu, Ag and Au). Ab initio lattice dynamics calculations have been p…
Spin-Phonon Coupling and High Pressure Phase Transitions of RMnO3 (R= Ca and Pr): An Inelastic Neutron Scattering and First Principle Studies
S. K. Mishra, M. K. Gupta, R. Mittal +2
We report inelastic neutron scattering measurements over 7-1251 K in CaMnO3 covering various phase transitions, and over 6-150 K in PrMnO3 covering the magnetic transition. The exc…
High Temperature Phase Stability in Li0.12Na0.88NbO3: A Combined powder X-Ray and Neutron Diffraction Study
S. K. Mishra, P. S. R. Krishna, A. B. Shinde +4
Lithium doped sodium niobate is an ecofriendly piezoelectric material that exhibits a variety of structural phase transitions with composition and temperature. We have investigated…
Close correlation between magnetic properties and the soft phonon mode of the structural transition in BaFeAs and SrFeAs
D. Parshall, L. Pintschovius, D. Lamago +4
Parent compounds of Fe-based superconductors undergo a structural phase transition from a tetragonal to an orthorhombic structure. We investigated the temperature dependence of the…
Inelastic Neutron Scattering Studies of Phonon Spectra and Simulations in Tungstates, AWO4 (A = Ba, Sr, Ca and Pb)
Prabhatasree Goel, M. K. Gupta, R. Mittal +4
Lattice dynamics and high pressure phase transitions in AWO4 (A = Ba, Sr, Ca and Pb) have been investigated using inelastic neutron scattering experiments, ab-initio density functi…
Spin-Phonon Coupling, High Pressure Phase Transitions and Thermal Expansion of Multiferroic GaFeO3: A Combined First Principles and Inelastic Neutron Scattering Study
M. K. Gupta, R. Mittal, M. Zbiri +4
We have carried out an extensive phonon study on multiferroic GaFeO3 to elucidate its dynamical behavior. Inelastic neutron scattering measurements are performed over a wide temper…
Phonons and Thermodynamics of LiMPO4 (M=Mn, Fe)
Prabhatasree Goel, M. K. Gupta, R. Mittal +5
Lithium transition metal phospho-olivines are useful electrode materials, owing to their stability, high safety, low cost and cyclability. We report phonon studies using neutron in…
Negative Thermal Expansion in cubic ZrW2O8: Role of Phonons in Entire Brillouin Zone From ab-inito Calculations
M. K. Gupta, R. Mittal, S. L. Chaplot
We report ab-inito density functional theory calculation of phonons in cubic phase of ZrW2O8 in the entire Brillouin zone and identify specific anharmonic phonons that are responsi…
Evidence for anomalous structural behavior in CaFe2As2
S. K. Mishra, R. Mittal, P. S. R. Krishna +5
The structural properties of the CaFe2As2 have been investigated by x-ray and neutron powder diffraction techniques as a function of temperature. Unambiguous experimental evidence…
Spin-Lattice Coupling in K0.8Fe1.6Se2 and KFe2Se2: Inelastic Neutron Scattering and ab-initio Phonon Calculations
R. Mittal, M. K. Gupta, S. L. Chaplot +6
We report measurements of the temperature dependence of phonon densities of states in K0.8Fe1.6Se2 using inelastic neutron scattering technique. While cooling down to 150 K, a phon…
Suppression of Antiferroelectric State in NaNbO3 at High Pressure from In Situ Neutron Diffraction
S. K. Mishra, M. K. Gupta, R. Mittal +2
We report direct experimental evidence of antiferroelectric to paraelectric phase transition under pressure in NaNbO3 using neutron diffraction at room temperature. The paraelectri…
High-Temperature Phonon Spectra of Multiferroic BiFeO3 from Inelastic Neutron Spectroscopy
M. Zbiri, H. Schober, N. Choudhury +5
We report inelastic neutron scattering measurements of the phonon spectra in a pure powder sample of the multiferroic material BiFeO3. A high-temperature range was covered to unrav…
Strong coupling of Sm and Fe magnetism in SmFeAsO as revealed by magnetic x-ray scattering
S. Nandi, Y. Su, Y. Xiao +17
The magnetic structures adopted by the Fe and Sm sublattices in SmFeAsO have been investigated using element specific x-ray resonant and non-resonant magnetic scattering techniques…
Phase stability and structural temperature dependence in sodium niobate: A high resolution powder neutron diffraction study
S. K. Mishra, R. Mittal, V. Yu. Pomjakushin +1
We report investigation of structural phase transitions in technologically important material sodium niobate as a function of temperature on heating over 300-1075 K. Our high resol…
Relationship Between Phonons and Thermal Expansion in Zn(CN)2 and Ni(CN)2 from Inelastic Neutron Scattering and Ab-Initio Calculations
R Mittal, M. Zbiri, H. Schober +4
Zn(CN)2 and Ni(CN)2 are known for exhibiting anomalous thermal expansion over a wide temperature range. The volume thermal expansion coefficient for the cubic, three dimensionally…
Magnetic correlations in spin ice Ho2-xYxTi2O7 as revealed by neutron polarization analysis
L. J. Chang, Y. Su, Y. -J. Kao +6
We present single-crystal neutron-diffuse-scattering measurements with polarization analysis on the spin ice Ho2-xYxTi2O7 (x = 0, 0.3, and 1). At 2 K, the spin flip scattering patt…
Magnetic structure of EuFe2As2 determined by single crystal neutron diffraction
Y. Xiao, Y. Su, M. Meven +9
Among various parent compounds of iron pnictide superconductors, EuFe2As2 stands out due to the presence of both spin density wave of Fe and antiferromagnetic ordering (AFM) of the…
Competing antiferroelectric and ferroelectric interactions in NaNbO3 : Neutron diffraction and theoretical studies
S. K. Mishra, N. Choudhury, S. L. Chaplot +2
Neutron diffraction studies using powder samples have been used to understand the complex sequence of low temperature phase transitions of NaNbO3 in the temperature range from 12 K…