Ames Laboratory; Physics and Astronomy
Ames Laboratory, Physics and Astronomy
Physical Review B
In the nematic state of iron-based superconductors, twin formation often obscures the intrinsic, anisotropic, in-plane physical properties. Relatively high in-plane external magnetic fields Hext greater than the typical laboratory-scale magnetic fields 10–15 T are usually required to completely detwin a sample. However, recently a very small in-plane Hext∼0.1 T was found to be sufficient for detwinning the nematic domains in EuFe2As2. To explain this behavior, a microscopic theory based on biquadratic magnetic interactions between the Eu and Fe spins has been proposed. Here, using 153Eu nuclear magnetic resonance (NMR) measurements below the Eu2+ ordering temperature, we show experimental evidence of the detwinning under small in-plane Hext. Our NMR study also reveals the evolution of the angles between the Eu and Fe spins during the detwinning process, which provides experimental evidence for the existence of biquadratic coupling in the system.
DOE Contract Number(s)
Department of Energy Subject Categories
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE
Iowa State University Digital Repository, Ames IA (United States)