Crystal structure, magnetic and electric properties of ternary neodymium stannides

New ternary Nd12Co6Sn and Nd6Co2Sn compounds were found in the Nd-rich part of the investigated Nd-Co-Sn system. The Nd12Co6Sn intermetallic compound crystallizes with the Sm12Ni6In structure type (space group Im3, a = 0.9861(2) nm). The crystal structure of the Nd6Co2Sn stannide belongs to the Ho6Co2Ga structure type (space group Immm, a = 0.9268(7) nm, b = 0.9285(7) nm, c = 0.9839(9) nm). A thermally induced transition was observed in the Nd12Co6Sn compound at 957 K. A nearly linear temperature dependence of the resistivity was observed and the thermopower in the 78-380 K range was measured for both compounds. The negative thermopowers increased in absolute value with increasing temperature. Curie-Weiss type behavior of the paramagnetic susceptibilities in the 80-450 K temperature range was observed and effective magnetic moments of 3.81 mu(B) and 3.42 mu(B) per Nd atom were calculated in the Nd12Co6Sn and Nd6Co2Sn, respectively. The Curie-Weiss intercepts were found to be 18 and 31 K for these two compounds, respectively. (C) 2003 Elsevier B.V. All rights reserved.