DPG Phi
Verhandlungen
Verhandlungen
DPG

Regensburg 2013 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

TT: Fachverband Tiefe Temperaturen

TT 55: Correlated Electrons: Low-Dimensional Systems -Materials 2

TT 55.3: Talk

Thursday, March 14, 2013, 10:00–10:15, H21

Impurity effects in a S=1/2 Heisenberg spin chain probed by 63Cu NMR — •Yannic Utz1, Eva Maria Brüning1, Franziska Hammerath1, Christian Rudisch1, Hans-Joachim Grafe1, Ashwin Mohan1, Romuald Saint-Martin2, Alexandre Revcolevschi2, Christian Hess1, Satoshi Nishimoto1, Stefan-Ludwig Drechsler1, and Bernd Büchner11IFW Dresden, Germany — 2LPCES, Orsay, France

We present 63Cu NMR measurements on undoped, Ni doped and Mg doped SrCuO2 single crystals. SrCuO2 is a good realization of a one-dimensional S=1/2 Heisenberg spin chain. This is confirmed by the theoretically-expected temperature independent NMR spin-lattice relaxation rate T1−1. Doping with Ni, which can be regarded as a S=1 impurity, has a major impact on the magnetic properties of the spin chains. On the one hand, this is manifested by unusual features in the NMR spectra below 100 K, revealing the existence of an impurity-induced local alternating magnetisation. On the other hand, exponentially decacying spin lattice relaxation rates towards low temperatures indicate the opening of a spin gap similar to Ca doped SrCuO2 [1]. Mg doping (S=0) has, however, no influence on the magnetic properties of the spin chains. Neither the NMR spectra nor the spin lattice relaxation rates differ from those measured on pure SrCuO2. While the different impact of Ni and Mg doping on the spin chains could be explained by their different impurity spins, the opening of a spin gap in case of Ni doping is totally unexpected and not yet understood.
[1] F. Hammerath et al., Phys. Rev. Lett. 107, 017203 (2011).

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2013 > Regensburg