Short-range magnetic ordering in the highly frustrated pyrochlore Y 2 Mn 2 O 7

摘要: The bulk magnetic susceptibility of ${\mathrm{Y}}_{2}$${\mathrm{Mn}}_{2}$${\mathrm{O}}_{7}$ is suggestive ferromagnetic order, with ${\mathit{FTHETA}}_{\mathit{C}}$=+41(2) K, and an apparent ${\mathit{T}}_{\mathit{c}}$=20 K. However, both dc ac data show a broad maximum near 7 which frequency field dependent. Heat-capacity studies down to 2 K no evidence for long-range order. Neutron-scattering indicate the presence antiferromagnetic (first neighbors) (second third short-range correlations. These results are compared mean-field-theory predictions highly frustrated 16c sites in pyrochlore lattice. This material shows many properties common spin glasses spite fact that there chemical disorder.