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 CuCrO 2 single crystal using nuclear magnetic and nuclear quadrupole resonances on 63,65 Cu nuclei are presented. The measurements have been carried out in wide ranges of temperature ( T = 4.2–300 K) and magnetic-field strength ( Н = 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 (χ a,c ). The hyperfine field on a copper nucleus has been determined, which is equal to h hf a,c = 33 kOe/μB. Below the temperature Т N = 23.6 K, nuclear magnetic resonance and nuclear quadrupole resonance spectra for 63,65 Cu nuclei have been recorded typical of helical magnetic structures, which are incommensurable with the lattice period.