Strong coupling between Eu2+ spins and Fe2As2 layers in EuFe1.9Co0.1As2 observed with NMR
Abstract
A combination of x-ray diffraction, magnetization, and As75 nuclear magnetic resonance (NMR) experiments were performed on single-crystal EuFe1.9Co0.1As2. The strength of the hyperfine interaction between the As75 nuclei and the Eu2+ 4f states suggests a strong coupling between the Eu2+ moments and the Fe1.9Co0.1As2 layers. Such a strong interlayer coupling may be due to an indirect exchange interaction between the localized Eu2+ 4f moments, mediated by the Fe 3d conduction electrons. Magnetic susceptibility as well as As75-NMR measurements reveal a decrease of the SDW transition temperature to TSDW = 120 K as a result of Co doping. A change of the slope in the temperature dependence of the NMR frequency of the As75 lower-satellite line was observed at 225 K. At the same temperature also a change of the satellite line shape was found. These changes of the NMR spectra may be caused by the formation of a nematic phase below 225 K in EuFe1.9Co0.1As2.
- Publication:
-
Physical Review B
- Pub Date:
- April 2011
- DOI:
- 10.1103/PhysRevB.83.144516
- arXiv:
- arXiv:1010.5948
- Bibcode:
- 2011PhRvB..83n4516G
- Keywords:
-
- 74.70.-b;
- 76.60.-k;
- 75.30.Fv;
- 61.50.Ks;
- Superconducting materials;
- Nuclear magnetic resonance and relaxation;
- Spin-density waves;
- Crystallographic aspects of phase transformations;
- pressure effects;
- Condensed Matter - Superconductivity
- E-Print:
- 8 pages, 7 figures