CRYSTAL-CHEMISTRY AND MAGNETISM OF NEODYMIUM STANNIDES INCLUDING COMPOUNDS OF THE STRUCTURAL SERIES RENSN3N-2

The binary system Nd-Sn has been investigated employing X-ray powder techniques and magnetic susceptibility measurements up to 600 K and 6 T. The formation of the compounds Nd5Sn3, Nd5Sn4, Nd11Sn10, NdSn, "Nd3Sn5," and NdSn3 has been confirmed. New phases Nd2Sn5, Nd3Sn7, and NdSn2 have been observed and their crystal structures were found to be isotypic with the structure types of Ce2Sn5, Ce3Sn7, and NdSn2 (ZrGa2), respectively. Further representatives of the Ce2Sn5-, the Ce3Sn7-, and the NdSn2-type have been synthesized for La, Pr, and Sm. The lanthanum-containing compounds are diamagnets above 80 K. La2Sn5 and LaSn2 become superconducting at 5.4 and 3.6 K, respectively. Pr2Sn5 and PrSn2 exhibit metamagnetism, whereas Pr3Sn7 is a weak ferromagnet. Nd5Sn3 and Nd3Sn5 are metamagnets with Neél temperatures TN=40 K and TN=14 K, respectively, whereas Nd5Sn4, Nd11Sn10, NdSn, and Nd3Sn7 order ferromagnetically at 67, 75, 32, and 10.5 K, respectively. NdSn2, Nd2Sn5, and NdSn3 prove to be antiferromagnets at low temperatures. For the new samarium stannides Sm3Sn7 and SmSn2, peaks in the susceptibility curves at 20 and 32 K give evidence of antiferromagnetic spin structures. © 1992 Academic Press, Inc.