ELECTRONIC-PROPERTIES OF UCUSN

Crystallographic analysis shows that UCuSn does not form in the hexago nal CaIn2 structure as reported previously, but is an ordered ternary compound and forms in an orthorhombic structure (space group: P2(1)cn) . Bulk and neutron-diffraction measurements reveal that UCuSn orders a ntiferromagnetically below 62 K. At 4.2 K, high-field magnetization re veals a complex magnetization process with two metamagnetic transition s. Furthermore, bulk investigations show an additional anomaly at 25 K , but a smooth temperature dependence of various magnetic peaks down t o the lowest temperature gives no evidence for a second magnetic trans ition. Possible scenarios responsible for the drastic changes in the e lectronic properties around 25 K are discussed. (C) 1996 American Inst itute of Physics.