Magnetic states of Yb ions in the charge ordered phase of Yb4As3 determined by polarized-neutron scattering

In order to re-examine the Yb ion states in the charge ordered phase of Yb4 As3 below T-C = 288 K, a detailed polarized-neutron experiment has been per formed. It shows that a large magnetic moment mu(1) due to Yb3+ ions is ind uced at the sites aligning along the unique < 111 > direction, and this fac t is consistent with that in the previous study. However, the value of mu(I I) at the other sites is only about 2% of that of mu(I) at 5 T and 1.5 K, T hus, the charge order is found to be more perfect than the result of the pr evious study. It is remarkable that temperature and magnetic field dependen cies of mu(II) are close to those of a magnetically isolated moment. (C) 20 00 Elsevier Science B.V, All rights reserved.