Magnetic anisotropy in Yb4As3 with one-dimensional Yb3+ chains

We measured the magnetic susceptibility and the specific heat of a single-d omain sample of Yb4As3 under the magnetic field along the trigonal axis. Th e magnetic susceptibility in the charge ordered phase is very anisotropic a cid the upturn at low temperatures becomes smaller than that of the multi-d omain sample. The suppression in the specific heat by applied fields parall el to the trigonal axis becomes weak compared with that of the multi-domain sample, These results indicate that this anisotropy is explained by the al ternating Dzyaloshinsky-Moriya interaction and the effect of the alternatin g off-diagonal g-tensors expected from the symmetry of Yb3+ sites on the on e-dimensional chains. (C) 2000 Published by Elsevier Science B.V. All right s reserved.