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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159 Scopus citations

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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10.1103/PhysRevLett.101.167203

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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.

UR - https://www.scopus.com/pages/publications/54849435537

U2 - 10.1103/PhysRevLett.101.167203

DO - 10.1103/PhysRevLett.101.167203

M3 - Article

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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