SHORT-RANGE MAGNETIC ORDER IN THE FRUSTRATED PYROCHLORE ANTIFERROMAGNET CSNICRF6

In the pyrochlore antiferromagnets, the magnetic ions are situated at the vertices of a framework of corner-sharing tetrahedra. The result i s intense geometrical frustration of the magnetic interactions. We pre sent the results of a single-crystal neutron-diffraction study of the pyrochlore CsNiCrF6 to investigate the development of magnetic order a t low temperatures. We find that even at a temperature of 2 K (which i s below the apparent spin-glass transition), the order does not extend further than two nearest neighbors, in spite of the strong antiferrom agnetic interactions between spins. We also present the results of Mon te Carlo calculations of the magnetic scattering utilizing a simple mo del Hamiltonian, and find good qualitative agreement with the experime ntal data. [S0163-1829(97)02637-4].