NMR-STUDY OF THE MAGNETIC TRANSITION AND THE FERMI-LIQUID BEHAVIOR INYBAS

In order to clarify the magnetic properties of an Yb-monopnictide YbAs from a microscopic point of view, nuclear magnetic resonance and rela xation studies on As-75 have been carried out at low temperatures down to 20 mK. The NMR spectra between 0.4 and 0.6 K indicate that paramag netic and the antiferromagnetically ordered regions coexist. Below 0.2 K, the spin-lattice relaxation rate 1/T-1 shows Fermi-liquid-like beh avior given as 1/T1T = 2.9 (s K)(-1). From these results. it is conclu ded that YbAs is a heavy-fermion compound which undergoes an anomalous antiferromagnetic transition. (C) 1998 Elsevier Science B.V. All righ ts reserved.