Spin correlations in the dipolar pyrochlore antiferromagnet Gd2Sn2O7

Paddison, Joseph A. M.; Ehlers, Georg; Petrenko, O. A.; Wildes, A.; Gardner, J. S.; Stewart, J. R.

doi:10.1088/1361-648x/aa5d2e

“…Our choice of a Heisenberg model is motivated by the small orbital contribution to the magnetic moment (g ≈ 2.05) and ESR results above T N [36,37]. This is verified by a preliminary reverse Monte Carlo analysis [38][39][40][41] that reveals an isotropic distribution of spin orientations [see Sec. S3].…”

mentioning

confidence: 90%

Magnetic Excitations of the Classical Spin Liquid MgCr2O4

Bai

¹

,

Paddison

²

,

Kapit

³

et al. 2019

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We report a comprehensive inelastic neutron-scattering study of the frustrated pyrochlore antiferromagnet MgCr2O4 in its cooperative paramagnetic regime. Theoretical modeling yields a microscopic Heisenberg model with exchange interactions up to third-nearest neighbors, which quantitatively explains all the details of the dynamic magnetic response. Our work demonstrates that the magnetic excitations in paramagnetic MgCr2O4 are faithfully represented in the entire Brillouin zone by a theory of magnons propagating in a highly-correlated paramagnetic background. Our results also suggest that MgCr2O4 is proximate to a spiral spin-liquid phase distinct from the Coulomb phase, which has implications for the magneto-structural phase transition in MgCr2O4.

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“…where n(θ, φ) is the number spins with orientations within the range d(cos θ), dφ, and N is the total number of spins. It has been shown previously that RMC refinement is sensitive to anisotropy in pyrochlore magnets, if it is indeed present [36]. However, the function ln(p) for MgCr…”

Section: S3 Reverse Monte-carlo Analysis Of Spin-space Anisotropymentioning

confidence: 94%

“…We will show that it is crucial to model the two inequivalent third-neighbor pathways J 3a and J 3b separately. Our choice of a Heisenberg model is motivated by the small orbital contribution to the magnetic moment (g ≈ 2.05) and a preliminary reverse Monte Carlo analysis [34][35][36][37] that revealed an isotropic distribution of spin orientations [see Sec. S3].…”

Section: Fig 1 (A)mentioning

confidence: 99%

Magnetic excitations of the classical spin liquid MgCr2O4

Bai,

Paddison,

Kapit

et al. 2018

Preprint

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We report a comprehensive inelastic neutron-scattering study of the frustrated pyrochlore antiferromagnet MgCr2O4 in its cooperative paramagnetic regime. Theoretical modeling yields a microscopic Heisenberg model with exchange interactions up to third-nearest neighbors, which quantitatively explains all the details of the dynamic magnetic response. Our work demonstrates that the magnetic excitations in paramagnetic MgCr2O4 are faithfully represented in the entire Brillouin zone by a theory of magnons propagating in a highly-correlated paramagnetic background. Our results also suggest that MgCr2O4 is proximate to a spiral spin-liquid phase distinct from the Coulomb phase, which has implications for the magneto-structural phase transition in MgCr2O4.

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“…We use mean-field Onsager reaction field (MFO) theory [35,36] in order to estimate exchange interactions in the paramagnetic state. Real-space atomistic models of the paramagnetic scattering are produced via direct Monte Carlo simulations [18] using the SCATTY program [37] to calculate the expected single-crystal diffuse scattering.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Gd 2 Sn 2 O 7 is stabilized by a small ferromagnetic third nearneighbor interaction [18], shown as J 3b in Fig. 1.…”

Section: B-sitementioning

confidence: 98%

Magnetic structure and exchange interactions in the Heisenberg pyrochlore antiferromagnet Gd2Pt2O7

Welch

¹

,

Paddison

²

,

Le

³

et al. 2022

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The Heisenberg pyrochlore antiferromagnet Gd 2 Pt 2 O 7 is one of a series of gadolinium pyrochlore compounds with a variety of B-site cations. Despite the expected simplicity of a spin-only Gd 3+ Heisenberg interaction model, the gadolinium pyrochlore series exhibits various complex magnetic ground states at low temperature. Gd 2 Pt 2 O 7 displays the highest temperature magnetic order of the series with T N = 1.6 K, which has been attributed to enhanced superexchange pathways facilitated by empty 5d e g Pt orbitals. In this study, we use various neutron scattering techniques on an isotopically enriched polycrystalline 160 Gd 2 Pt 2 O 7 sample to examine the magnetic structure and spin-wave excitation spectrum below T N in order to extract the dominant exchange interactions. We find that the ground-state magnetic structure is the Palmer-Chalker state previously seen in Gd 2 Sn 2 O 7 with an associated gapped excitation spectrum consistent with enhanced exchange interactions between further near-neighbor Gd 3+ ions. We confirm this exchange model with analysis of the magnetic diffuse scattering in the paramagnetic regime using polarized neutrons.

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Spin correlations in the dipolar pyrochlore antiferromagnet Gd₂Sn₂O₇

Cited by 11 publications

References 47 publications

Magnetic Excitations of the Classical Spin Liquid MgCr2O4

Magnetic Excitations of the Classical Spin Liquid MgCr2O4

Magnetic excitations of the classical spin liquid MgCr2O4

Magnetic structure and exchange interactions in the Heisenberg pyrochlore antiferromagnet Gd2Pt2O7

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