Campus Units

Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

7-1-2012

Journal or Book Title

Physical Review B

Volume

86

Issue

2

First Page

024505

DOI

10.1103/PhysRevB.86.024505

Abstract

The magnetic excitations in the paramagnetic-tetragonal phase of underdoped Ba(Fe0.953Co0.047)(2)As-2, as measured by inelastic neutron scattering, can be well described by a phenomenological model with purely diffusive spin dynamics. At low energies, the spectrum around the magnetic ordering vector QAFM consists of a single peak with elliptical shape in momentum space. At high energies, this inelastic peak is split into two peaks across the direction perpendicular to QAFM. We use our fittings to argue that such a splitting is not due to incommensurability or propagating spin-wave excitations, but is rather a consequence of the anisotropies in the Landau damping and in the magnetic correlation length, both of which are allowed by the tetragonal symmetry of the system. We also measure the magnetic spectrum deep inside the magnetically ordered phase, and find that it is remarkably similar to the spectrum of the paramagnetic phase, revealing the strongly overdamped character of the magnetic excitations.

Comments

This article is published as Tucker, Gregory S., R. M. Fernandes, H-F. Li, Vivek Thampy, Ni Ni, Douglas L. Abernathy, Serguei L. Bud'ko, P. C. Canfield, D. Vaknin, J. Schmalian, and R. J. McQueeney. "Magnetic excitations in underdoped Ba (Fe 1− x Co x) 2 As 2 with x= 0.047." Physical Review B 86, no. 2 (2012): 024505. DOI: 10.1103/PhysRevB.86.024505. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

Share

COinS