Internal magnetic field in the zigzag-chain family (Na,Ca)Cr2O4

[摘要] In order to elucidate the magnetic nature for a novel one-dimensional zigzag chain compound, NaCr2O4, we have measured μ+SR spectra using a powder sample in the temperature range between 2 and 200 K. Weak transverse field (wTF-) μ+SR measurements indicated that the whole volume of the sample enters into an antiferromagnetic (AF) phase below TN 125 K. The zero field (ZF-) μ+SR spectrum obtained below TN exhibits a clear oscillation with a single muon-spin precession frequency (fμ). This suggests that static AF order is formed below TN and that all the implanted muons sense the same internal magnetic field. The temperature dependence of fμ was found to be very similar to that for the intensity of the magnetic Bragg peak in neutron diffraction (ND) measurements. On the other hand, the ZF-μ+SR spectrum for the isostructural compound, β-CaCr2O4, showed a rapidly damped oscillation below TN 21 K, supporting the formation of incommensurate AF order, as proposed by ND.

[发布机构] Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi; 480-1192, Japan^1;National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki; 305-0044, Japan^2;TRIUMF, 4004 Wesbrook Mall, Vancouver; BC; V6T 2A3, Canada^3;Department of Physics and Astronomy, University of British Columbia, Vancouver; BC; V6T 1Z1, Canada^4

[关键词] Antiferromagnetics;Damped oscillations;Internal magnetic fields;Isostructural compounds;Magnetic Bragg peaks;Temperature dependence;Temperature range;Transverse field