300 citations · 2.7k across the 72 of their papers we have counts for
29 papers · 1 filter
Lattice dynamics and spin excitations in the metal-organic framework [CHNH][Co(HCOO)]
Lei Ding, Claire V. Colin, Virginie Simonet +11
In metal-organic-framework (MOF) perovskites, both magnetic and ferroelectric orderings can be readily realized by compounding spin and charge degrees of freedom. The hydrogen bond…
Fast broadband cluster spin-glass dynamics in PbFeNbO
C. Stock, B. Roessli, P. M. Gehring +11
PbFeNbO (PFN) is a relaxor ferroelectric (T 400 K) consisting of disordered magnetic Fe (S=, L0) ions resulting in a l…
Relating spin-polarized STM imaging and inelastic neutron scattering in the van-der-Waals ferromagnet Fe3GeTe2
Christopher Trainer, Olivia R. Armitage, Harry Lane +7
Van-der-Waals (vdW) ferromagnets have enabled the development of heterostructures assembled from exfoliated monolayers with spintronics functionalities, making it important to unde…
Large dynamic scissoring mode displacements coupled to band gap opening in Hybrid Perovskites
Tobias A. Bird, Jungshen Chen, Manila Songvilay +4
Hybrid perovskites are a rapidly growing research area, having reached photovoltaic power conversion efficiencies of over 25 \%. We apply a symmetry-motivated analysis method to an…
Alignment facility and software for single crystal time of flight neutron spectroscopy
Z. Liu, H. Lane, C. D. Frost +3
An instrument and software algorithm is described for the purpose of characterization of large single crystals at the Alignment Facility (ALF) of the ISIS spallation neutron source…
Spin-wave directional anisotropies in antiferromagnetic BaNbFeSiO
C. Stock, R. D. Johnson, N. Giles-Donovan +14
BaNbFeSiO (langasite) is structurally and magnetically single domain chiral with the magnetic helicity induced through competing symmetric exchange interac…
Common acoustic phonon lifetimes in inorganic and hybrid lead halide perovskites
M. Songvilay, N. Giles-Donovan, M. Bari +12
The acoustic phonons in the organic-inorganic lead halide perovskites have been reported to have anomalously short lifetimes over a large part of the Brillouin zone. The resulting…
Electric field effect on short-range polar orders in a relaxor ferroelectric system
Zhijun Xu, Fei Li, Shujun Zhang +4
Short-range polar orders in the relaxor ferroelectric material PbMgNbO-PbTiO (PMN-28PT) have been studied using neutron diffuse scattering. An externa…
Incommensurate atomic and magnetic modulations in the spin-frustrated β-NaMnO2 triangular lattice
Fabio Orlandi, Eleni Aza, Ioanna Bakaimi +9
The layered β-NaMnO2, a promising Na-ion energy-storage material has been investigated for its triangular lattice capability to promote complex magnetic configurations that may rel…
Spin-wave induced phonon resonance in multiferroic BiFeO
Zhijun Xu, J. A. Schneeloch, Jinsheng Wen +13
We report the direct observation of a "resonance" mode in the lowest-energy optic phonon very near the zone center around (111) in the multiferroic BiFeO using neutron scatteri…
Spontaneous decay of a soft optical phonon in the relaxor ferroelectric PbMgNbO
C. Stock, P. M. Gehring, R. A. Ewings +4
We report the spontaneous decay of a soft, optical phonon in a solid. Using neutron spectroscopy, we find that specific phonon lifetimes in the relaxor PbMgNbO$_{3}…
Molecular orientational melting within a lead-halide octahedra framework - the order-disorder transition in CH3NH3PbBr3
K. L. Brown, S. F. Parker, I. Robles Garcia +3
Lead-halide organic-inorganic perovskites consist of an inorganic host framework with an organic molecule occupying the interstitial space. The structure and dynamics of these mate…
An Inelastic X-Ray investigation of the Ferroelectric Transition in SnTe
Christopher D. ONeill, Dmitry A. Sokolov, Andreas Hermann +4
We report that the lowest energy transverse-optic phonon in metallic SnTe softens to near zero energy at the structural transition at and importantly show that t…
Phonon coupling to dynamic short-range polar order in a relaxor ferroelectric near the morphotropic phase boundary
John A. Schneeloch, Zhijun Xu, B. Winn +4
We report neutron inelastic scattering experiments on single crystal PbMgNbO doped with 32\% PbTiO, a relaxor ferroelectric that lies close to the morph…
Fluctuating defects in the incipient relaxor KLiTaO (x=0.02)
C. Stock, P. M. Gehring, G. Xu +5
We report neutron scattering measurements of the structural correlations associated with the apparent relaxor transition in KLiTaO for (KLT(0.02)). This co…
Neutron inelastic scattering measurements of low energy phonons in the multiferroic BiFeO3
John A. Schneeloch, Zhijun Xu Jinsheng Wen, P. M. Gehring +11
We present neutron inelastic scattering measurements of the low-energy phonons in single crystal BiFeO3. The dispersions of the three acoustic phonon modes (LA along [100], TA1 alo…
The role of random electric fields in relaxors
D. Phelan, C. Stock, J. A. Rodriguez-Rivera +8
PbZr_{1-x}Ti_xO_3 (PZT) and Pb(Mg_{1/3}Nb_{2/3})_{1-x}Ti_xO_3 (PMN-PT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudorhombohedra…
Coupled magnetic and ferroelectric excitations in PbFe_{1/2}Nb_{1/2}O_{3}
C. Stock, S. R. Dunsiger, R. A. Mole +2
A neutron scattering investigation of the magnetoelectric coupling in PbFe_{1/2}Nb_{1/2}O_{3} (PFN) has been undertaken. Ferroelectric order occurs below 400 K, as evidenced by the…
Non-collinear spin-density wave antiferromagnetism in FeAs
E. E. Rodriguez, C. Stock, K. Krycka +6
We present the magnetic structure of the itinerant monoarsenide, FeAs, with the B31 structure. Powder neutron diffraction confirms incommensurate modulated magnetism with wavevecto…
Dynamic origin of the morphotropic phase boundary - Soft modes and phase instability in 0.68Pb(Mg1/3Nb2/3O3)-0.32PbTiO3
Hu Cao, Chris Stock, Guangyong Xu +3
We report neutron inelastic scattering on single crystal 0.68Pb(Mg1/3Nb2/3O3)-0.32PbTiO3 (PMN-0.32PT), a relaxor ferroelectric material that lies within the compositional range of…
Orbital ordering promotes weakly-interacting S=1/2 dimers in the triangular lattice compound Sr3Cr2O8
L. C. Chapon, C. Stock, P. G. Radaelli +1
The weakly interacting S=1/2 dimers system Sr3Cr2O8 has been investigated by powder neutron diffraction and inelastic neutron scattering. Our data reveal a structural phase transit…
The effect of local dipole moments on the structure and lattice dynamics of K0.98Li0.02TaO3
Jinsheng Wen, Guangyong Xu, C. Stock +5
We present high energy x-ray (67 keV) and neutron scattering measurements on a single crystal of KLiTaO for which the Li content () is less than $x_c = 0.02…
Response of polar nanoregions in 68%Pb(Mg1/3Nb2/3)O3-32%PbTiO3 to a [001] electric field
Jinsheng Wen, Guangyong Xu, C. Stock +1
We report neutron diffuse scattering measurements on a single crystal of 68%Pb(Mg1/3Nb2/3)O3-32%PbTiO3. Strong diffuse scattering is observed at low temperatures. An external field…
Phase instability induced by polar nanoregions in a relaxor ferroelectric system
Guangyong Xu, Jinsheng Wen, C. Stock +1
Local inhomogeneities known as polar nanoregions (PNR) play a key role in governing the dielectric properties of relaxor ferroelectrics - a special class of material that exhibits…