Low energy spin waves and magnetic interactions in SrFe2As2

Jun Zhao; Dao Xin Yao; Shiliang Li; Tao Hong; Y. Chen; S. Chang; W. Ratcliff; J. W. Lynn; H. A. Mook; G. F. Chen; J. L. Luo; N. L. Wang; E. W. Carlson; Jiangping Hu; Pengcheng Dai

doi:10.1103/PhysRevLett.101.167203

Low energy spin waves and magnetic interactions in SrFe2As2

Jun Zhao, Dao Xin Yao, Shiliang Li, Tao Hong, Y. Chen, S. Chang, W. Ratcliff, J. W. Lynn, H. A. Mook, G. F. Chen, J. L. Luo, N. L. Wang, E. W. Carlson, Jiangping Hu, Pengcheng Dai

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Abstract

We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (TN=200-220K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7K), the magnetic spectrum S(Q, □ ω) consists of a Bragg peak at the elastic position (□ ω=0meV), a spin gap (Δ≤6.5meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across TN, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.

Original language	English
Article number	167203
Journal	Physical Review Letters
Volume	101
Issue number	16
DOIs	https://doi.org/10.1103/PhysRevLett.101.167203
State	Published - Oct 14 2008

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title = "Low energy spin waves and magnetic interactions in SrFe2As2",

abstract = "We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (TN=200-220K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7K), the magnetic spectrum S(Q, □ ω) consists of a Bragg peak at the elastic position (□ ω=0meV), a spin gap (Δ≤6.5meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across TN, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.",

author = "Jun Zhao and Yao, {Dao Xin} and Shiliang Li and Tao Hong and Y. Chen and S. Chang and W. Ratcliff and Lynn, {J. W.} and Mook, {H. A.} and Chen, {G. F.} and Luo, {J. L.} and Wang, {N. L.} and Carlson, {E. W.} and Jiangping Hu and Pengcheng Dai",

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doi = "10.1103/PhysRevLett.101.167203",

language = "English",

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TY - JOUR

T1 - Low energy spin waves and magnetic interactions in SrFe2As2

AU - Zhao, Jun

AU - Yao, Dao Xin

AU - Li, Shiliang

AU - Hong, Tao

AU - Chen, Y.

AU - Chang, S.

AU - Ratcliff, W.

AU - Lynn, J. W.

AU - Mook, H. A.

AU - Chen, G. F.

AU - Luo, J. L.

AU - Wang, N. L.

AU - Carlson, E. W.

AU - Hu, Jiangping

AU - Dai, Pengcheng

PY - 2008/10/14

Y1 - 2008/10/14

N2 - We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (TN=200-220K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7K), the magnetic spectrum S(Q, □ ω) consists of a Bragg peak at the elastic position (□ ω=0meV), a spin gap (Δ≤6.5meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across TN, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.

AB - We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (TN=200-220K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7K), the magnetic spectrum S(Q, □ ω) consists of a Bragg peak at the elastic position (□ ω=0meV), a spin gap (Δ≤6.5meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across TN, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.

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U2 - 10.1103/PhysRevLett.101.167203

DO - 10.1103/PhysRevLett.101.167203

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AN - SCOPUS:54849435537

SN - 0031-9007

VL - 101

JO - Physical Review Letters

JF - Physical Review Letters

IS - 16

M1 - 167203

ER -

Low energy spin waves and magnetic interactions in SrFe2As2

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