NMR properties of CoRhP: mixing between Co and Rh sites

NMR properties of Co-59 and P-31 ill CoRhP with orthorhombic TiNiSi structure are reported. Field-swept NMR spectra of Co-59 show very broad ones from nonmagnetic Co sites where satellite peaks due to quadrupole interaction are smeared out. Thr Fourier transformed spectrum of P-31 NMR has two peaks. It is suggested that the Co and Rh atoms do not older but their sites are mixed. The mixing is consistent with ii Rietvelt analysis of X-ray diffraction powder patterns where a mixing of 10% of Co atoms into Rh sites is estimated. This kind of mixing seems to be one of the origins of the variety of magnetic and electric properties of MRuP and MRhP (M=3d transition metal) systems. The nuclear spin-lattice relaxation rates of Co-59 and P-31 in CoRhP obey Korringa relations at high temperatures anti the!; show stepwise decreases with decreasing temperature at 11 K where the static susceptibility has a peak. The behaviors are interpreted as an onset of a charge density wave (CDW) at 11 K rather than an onset of an antiferromagnetism. (C) 2001 Elsevier science B.V. All rights reserved