We studied magnetic phase diagram and x-dependence of spiral spin correlation in magnetically ordered phase of (Co 1-xZn x)Cr 2O 4 by magnetization and neutron scattering experiments. The spiral correlation survives in a wide × range from 0 to 0.9. As × increases, the correlation length decreases from ξ ∼ 23 Å at × - 0, and saturates at ξ ∼ 2:5 Å at around × - 0:75, which is close to the nearest neighboring Cr 3+-Cr 3+ distance. The pitch is almost constant from × - 0 to 0.75, then abruptly shortens above around × - 0:75. The correlation is isotropic at × = 0:25 but anisotropic at × = 0:75. We discuss that the spiral correlation is of short-range owing to unquenched geometric frustration, and begins to collapse with the minimization of correlation length above around × - 0:75, possibly as the precursor of dynamic spin hexamer caused by high geometric frustration.
ASJC Scopus subject areas
- Physics and Astronomy(all)