Specific features of magnetic order in a multiferroic compound CuCrO2 determined using NMR and NQR data for 63, 65Cu nuclei

Results of studying the paramagnetic and ordered phases of a CuCrO2 single crystal using nuclear magnetic and nuclear quadrupole resonances on Cu-63,Cu-65 nuclei are presented. The measurements have been carried out in wide ranges of temperature (T = 4.2-300 K) and magnetic-field strength (De = 0-94 kOe), with the magnetic fields being directed along a and c axes of the crystal. The components of the electric-field gradient tensor and the magnetic-shift tensor (K (a,c)) have been determined. The temperature dependences K (a)(H || a) and K (c)(H || c) for the paramagnetic phase are described by the Curie-Weiss law and reproduce the behavior of the magnetic susceptibility (chi(a,c)). The hyperfine field on a copper nucleus has been determined, which is equal to h (hf) (a,c) = 33 kOe/mu B. Below the temperature D cent (N) = 23.6 K, nuclear magnetic resonance and nuclear quadrupole resonance spectra for Cu-63,Cu-65 nuclei have been recorded typical of helical magnetic structures, which are incommensurable with the lattice period.