Magneto resistance measurements in UCu4+xAl8-x compounds

The intermetallic Ucu(4+x)Al(8-x) compounds (0.1 less than or equal to x le ss than or equal to 1.95) have remarkable electronic and magnetic propertie s. The Cu-poor compositions within this x-range are antiferromagnetic (AF). The Neel temperature (T-N) drops gradually from approximate to 36 K for x = 0.1 until AF is completely suppressed near x = 1.1. while the Sommerfeld coefficient (gamma) increases dramatically with x. reaching a maximum value of 750 mJ/mol K-2 for x = 1.75. Reported in this investigation are magneto resistance (MR) and magnetic susceptibility (chi) measurements at low temp eratures (T) and high magnetic fields (B). The isothermal MR data below 40 K crosses over from positive in the low-x to negative in the high-x range. These results are interpreted in the context of spin fluctuations. hybridiz ation, and non-magnetic atomic disorder. (C) 2001 Elsevier Science B.V. All rights reserved.