Campus Units
Physics and Astronomy, Ames Laboratory
Document Type
Article
Publication Version
Published Version
Publication Date
11-1-2015
Journal or Book Title
Physical Review B
Volume
92
Issue
18
First Page
184504
DOI
10.1103/PhysRevB.92.184504
Abstract
We report 75As nuclear magnetic resonance (NMR) measurements of single-crystalline Ca(Fe1−xCox)2As2 (x=0.023, 0.028, 0.033, and 0.059) annealed at 350∘C for 7 days. From the observation of a characteristic shape of 75As NMR spectra in the stripe-type antiferromagnetic (AFM) state, as in the case of x=0 (TN=170 K), clear evidence for the commensurate AFM phase transition with the concomitant structural phase transition is observed in x=0.023 (TN=106 K) and x=0.028 (TN=53 K). Through the temperature dependence of the Knight shifts and the nuclear spin lattice relaxation rates (1/T1), although stripe-type AFM spin fluctuations are realized in the paramagnetic state as in the case of other iron pnictide superconductors, we found a gradual decrease of the AFM spin fluctuations below a crossover temperature T∗ that was nearly independent of Co-substitution concentration, and it is attributed to a pseudogaplike behavior in the spin excitation spectra of these systems. The T∗ feature finds correlation with features in the temperature-dependent interplane resistivity, ρc(T), but not with the in-plane resistivity ρa(T). The temperature evolution of anisotropic stripe-type AFM spin fluctuations is tracked in the paramagnetic and pseudogap phases by the 1/T1 data measured under magnetic fields parallel and perpendicular to the c axis. Based on our NMR data, we have added a pseudogaplike phase to the magnetic and electronic phase diagram of Ca(Fe1−xCox)2As2.
Copyright Owner
American Physical Society
Copyright Date
2015
Language
en
File Format
application/pdf
Recommended Citation
Cui, Jun; Roy, B.; Tanatar, Makariy A.; Ran, S.; Bud’ko, Sergey L.; Prozorov, Ruslan; Canfield, Paul C.; and Furukawa, Yuji, "Antiferromagnetic spin correlations and pseudogaplike behavior in Ca(Fe1-xCox)(2)As-2 studied by As-75 nuclear magnetic resonance and anisotropic resistivity" (2015). Physics and Astronomy Publications. 596.
https://lib.dr.iastate.edu/physastro_pubs/596
Comments
This article is published as Cui, J., B. Roy, M. A. Tanatar, S. Ran, S. L. Bud'ko, R. Prozorov, P. C. Canfield, and Y. Furukawa. "Antiferromagnetic spin correlations and pseudogaplike behavior in Ca (Fe 1− x Co x) 2 As 2 studied by As 75 nuclear magnetic resonance and anisotropic resistivity." Physical Review B 92, no. 18 (2015): 184504. DOI: 10.1103/PhysRevB.92.184504. Posted with permission.