NMR study of the high-field magnetic phase of LiCuVO$_4$

Autor: Buttgen, N., Kraetschmer, W., Svistov, L. E., Prozorova, L. A., Prokofiev, A.
Rok vydání: 2009
Předmět:
Zdroj: Phys. Rev. B Vol. 81, 052403 (2010)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevB.81.052403
Popis: We report on NMR studies of the quasi--1D antiferromagnetic $S=1/2$ chain cuprate LiCuVO$_4$, focusing on the high--field spin--modulated phase observed recently in applied magnetic fields $H > H_{\rm c2}$ ($\mu_0H_{\rm c2} \approx 7.5$ T). The NMR spectra of $^7$Li and $^{51}$V around the transition from the ordered to the paramagnetic state were measured. It is shown that the spin--modulated magnetic structure forms with ferromagnetic interactions between spins of neighboring chains within the {\bf ab}--plane at low temperatures 0.6 K $ < T < T_{\rm N}$. The best fit provides evidence that the mutual orientation between spins of neighboring {\bf ab}--planes is random. For elevated temperatures $T_{\rm N} < T \lesssim 15$ K, short--range magnetic order occurs at least on the characteristic time scale of the NMR experiment.
Comment: 5 pages, 5 figures
Databáze: arXiv