One-dimensional magnetic state in the charge-ordered phase of Yb4As3 investigated by polarized-neutron measurements

Polarized-neutron diffraction study on Yb4As3 revealed that one-dimensional (1D) chains of magnetic Yb3+ ions are formed by the charge ordering. The field-induced magnetic moments of this 1D chains under the field parallel to the chains behave as that of the spin-1/2 1D Heisenberg antiferromagnet with g sub(parallel) = 3.0. In the case of the field perpendicular to the chain, we observed not only the same behavior of induced moments with g sub(perpendicular) = 1.2 at high temperatures but also a pronounced enhancement below about 10 K. The observed enhancement of 1D magnetization can be reproduced well by the theory which takes into account the staggered-field effect due to the Dzyaloshinsky-Moriya interaction. (author)