Crystal Growth of Oxides by Optical Floating Zone Technique

Dąbkowska, H. A.; Dąbkowski, A.

doi:10.1007/978-3-540-74761-1_12

Cited by 50 publications

(43 citation statements)

References 130 publications

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“…of air and with a growth rate of 7 mm h −1 . This method of crystal growth is well-established for the rare earth titanate pyrochlores [18][19][20]. This crystal was cut into two 2-3 gram segments, which were respectively aligned in the (H,K,0) and the (K+H,K−H,−2K) scattering planes using x-ray Laue diffraction.…”

Section: Methodsmentioning

confidence: 99%

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

et al. 2017

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The XY pyrochlore antiferromagnet Er2Ti2O7 exhibits a rare case of Z6 discrete symmetry breaking in its ψ2 magnetic ground state. Despite being well-studied theoretically, systems with high discrete symmetry breakings are uncommon in nature and, thus, Er2Ti2O7 provides an experimental playground for the study of broken Zn symmetry, for n > 2. A recent theoretical work examined the effect of a magnetic field on a pyrochlore lattice with broken Z6 symmetry and applied it to Er2Ti2O7. This study predicted multiple domain transitions depending on the crystallographic orientation of the magnetic field, inducing rich and controllable magnetothermodynamic behavior. In this work, we present neutron scattering measurements on Er2Ti2O7 with a magnetic field applied along the [001] and [111] directions, and provide the first experimental observation of these exotic domain transitions. In a [001] field, we observe a ψ2 to ψ3 transition at a critical field of 0.18 ± 0.05 T. We are thus able to extend the concept of the spin-flop transition, which has long been observed in Ising systems, to higher discrete Zn symmetries. In a [111] field, we observe a series of domain-based phase transitions for fields of 0.15 ± 0.03 T and 0.40 ± 0.03 T. We show that these field-induced transitions are consistent with the emergence of two-fold, three-fold and possibly six-fold Zeeman terms. Considering all the possible ψ2 and ψ3 domains, these Zeeman terms can be mapped onto an analog clock -exemplifying a literal clock anisotropy. Lastly, our quantitative analysis of the [001] domain transition in Er2Ti2O7 is consistent with order-by-disorder as the dominant ground state selection mechanism.

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Section: Methodsmentioning

confidence: 99%

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

et al. 2017

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“…The growths followed the protocols already reported for the nonsuperconducting samples [24][25][26] .…”

Section: Methodsmentioning

confidence: 99%

Neutron scattering studies of spin-phonon hybridization and superconducting spin gaps in the high-temperature superconductorLa2−x(Sr,Ba)xCuO
Wagman
¹
,
Carlo
²
,
Gaudet
³

et al. 2016
Phys. Rev. B
13
9
2
1
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We present time-of-flight neutron-scattering measurements on single crystals of La2−xBaxCuO4 (LBCO) with 0 ≤x≤ 0.095 and La2−xSrxCuO4 (LSCO) with x = 0.08 and 0.11. This range of dopings spans much of the phase diagram relevant to high temperature cuprate superconductivity, ranging from insulating, three dimensional (3D) commensurate long range antiferromagnetic order, for x ≤ 0.02, to two dimensional (2D) incommensurate antiferromagnetism co-existing with superconductivity for x ≥ 0.05. Previous work on lightly doped LBCO with x = 0.035 showed a clear resonant enhancement of the inelastic scattering coincident with the low energy crossings of the highly dispersive spin excitations and quasi-2D optic phonons. The present work extends these measurements across the phase diagram and shows this enhancement to be a common feature to this family of layered quantum magnets. Furthermore we show that the low temperature, low energy magnetic spectral weight is substantially larger for samples with non-superconducting ground states relative to any of the samples with superconducting ground states. Spin gaps, suppression of low energy magnetic spectral weight as a function of decreasing temperature, are observed in both superconducting LBCO and LSCO samples, consistent with previous observations for superconducting LSCO.

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“…The growth method has been reported on previously 37,38 . The resulting samples were cylindrical in shape and weighed ∼ 7 grams each.…”

Section: Methodsmentioning

confidence: 99%

Two-dimensional incommensurate and three-dimensional commensurate magnetic order and fluctuations in La2−xBaxCuO

et al. 2013

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We present neutron scattering measurements on single crystals of lightly doped La2−xBaxCuO4, with 0 ≤ x ≤ 0.035. These reveal the evolution of the magnetism in this prototypical doped Mott insulator from a three dimensional (3D) commensurate (C) antiferromagnetic ground state, which orders at a relatively high TN , to a two dimensional (2D) incommensurate (IC) ground state with finite ranged static correlations, which appear below a relatively low effective TN . At low temperatures, the 2D IC magnetism co-exists with the 3D C magnetism for doping concentrations as low as ∼ 0.0125. We find no signal of a 3D C magnetic ground state by x ∼ 0.025, consistent with the upper limit of x ∼ 0.02 observed in the sister family of doped Mott insulators, La2−xSrxCuO4. The 2D IC ground states observed for 0.0125 ≤ x ≤ 0.035 are diagonal, and are rotated by 45 degrees within the orthorhombic basal plane compared with those previously reported for samples with superconducting ground states: La2−xBaxCuO4, with 0.05 ≤ x ≤ 0.095. We construct a phase diagram based solely on magnetic order parameter measurements, which displays much of the complexity of standard high temperature superconductivity phase diagrams discussed in the literature. Analysis of high energy-resolution inelastic neutron scattering at moderately low temperatures shows a progressive depletion of the very low energy dynamic magnetic susceptibility as x increases from 0.0125 to 0.035. This low energy, dynamic susceptibility falls off with increasing temperature on a scale much higher than the effective 2D IC TN appropriate to these materials. Appreciable dynamic 2D IC magnetic fluctuations inhabit much of the "pseudogap" regime of the phase diagram.

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Crystal Growth of Oxides by Optical Floating Zone Technique

Cited by 50 publications

References 130 publications

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

Neutron scattering studies of spin-phonon hybridization and superconducting spin gaps in the high-temperature superconductorLa2−x(Sr,Ba)xCuO
Wagman
¹
,
Carlo
²
,
Gaudet
³

et al. 2016
Phys. Rev. B
13
9
2
1
View full text Add to dashboard Cite

Two-dimensional incommensurate and three-dimensional commensurate magnetic order and fluctuations in La2−xBaxCuO

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Crystal Growth of Oxides by Optical Floating Zone Technique

Cited by 50 publications

References 130 publications

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

Experimental evidence for field-induced emergent clock anisotropies in the XY pyrochlore Er2Ti2O7

Neutron scattering studies of spin-phonon hybridization and superconducting spin gaps in the high-temperature superconductorLa2−x(Sr,Ba)xCuOWagman1, Carlo2, Gaudet3 et al. 2016Phys. Rev. B13921View full textAdd to dashboardCite

Two-dimensional incommensurate and three-dimensional commensurate magnetic order and fluctuations in La2−xBaxCuO

Contact Info

Product

Resources

About

Neutron scattering studies of spin-phonon hybridization and superconducting spin gaps in the high-temperature superconductorLa2−x(Sr,Ba)xCuO
Wagman
¹
,
Carlo
²
,
Gaudet
³

et al. 2016
Phys. Rev. B
13
9
2
1
View full text Add to dashboard Cite