No evidence of the crossover in the spin fluctuations of Ca(Fe1-xCox)2As2 and unusual suppression with temperature for x = 0.030.

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APS March Meeting 2018

Volume 63, Number 1

Monday–Friday, March 5–9, 2018; Los Angeles, California

Session X11: Fe-based superconductivity - Neutron scattering and magnetism

8:00 AM–10:48 AM, Friday, March 9, 2018
LACC Room: 303A

Sponsoring Units: DMP GMAG
Chair: Songxue Chi, Oak Ridge National Lab

Abstract ID: BAPS.2018.MAR.X11.5

Abstract: X11.00005 : No evidence of the crossover in the spin fluctuations of Ca(Fe_1-xCo_x)₂As₂and unusual suppression with temperature for x = 0.030.*

9:12 AM–9:24 AM

Abstract

Presenter:

Aashish Sapkota
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Authors:

Aashish Sapkota
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Pinaki Das
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Anna Boehmer
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Benjamin Ueland
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Douglas Abernathy
(Oak Ridge National Laboratory)

Sergey Budko
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Paul Canfield
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Andreas Kreyssig
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Alan Goldman
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

Robert McQueeney
(Dept. of Physics and Astronomy, Ames Laboratory/Iowa State University)

In the Ca(Fe_1-xCo_x)₂As₂family, the superconductivity appears with Co doping after a first-order suppression of an antiferromagnetic order. Here, we present results of our inelastic neutron scattering measurement on Ca(Fe_1-xCo_x)₂As₂, x=0.026 (antiferromagnetically ordered below T_N=64±7 K) and x=0.030 (superconducting below T_c=14.6±1 K). Our results suggest that, unlike Ba(Fe_1-xCo_x)₂As₂, smooth evolution of the gapped spin waves to diffusive spin fluctuations is absent in Ca(Fe_1-xCo_x)₂As₂ and the result is consistent with the first order phase transition from magnetically ordered to superconducting state. Additionally, we observed an unusual suppression of the spin fluctuations with decreasing temperature for x=0.030, possibly arising due to compound’s proximity to the collapsed tetragonal phase.

*Work at the Ames Laboratory was supported by US DOE, Basic Energy Sciences, Division of Material Sciences and Engineering, under contract No. DE-AC02-07CH11358. This research used resources of SNS, a DOE office of science user facility operated by ORNL.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.MAR.X11.5

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Bulletin of the American Physical Society

APS March Meeting 2018

Volume 63, Number 1

Monday–Friday, March 5–9, 2018; Los Angeles, California

Session X11: Fe-based superconductivity - Neutron scattering and magnetism

Abstract: X11.00005 : No evidence of the crossover in the spin fluctuations of Ca(Fe1-xCox)2As2 and unusual suppression with temperature for x = 0.030.*

Presenter:

Authors:

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Abstract: X11.00005 : No evidence of the crossover in the spin fluctuations of Ca(Fe_1-xCo_x)₂As₂and unusual suppression with temperature for x = 0.030.*