Magnetic behavior of the ternary silicide U3Cu4Si4

The orthorhombic ternary silicide U3Cu4Si4 has been studied by means of ele ctrical resistivity, AC- and DC-magnetization measurements and neutron powd er diffraction. Magnetic measurements reveal that U3Cu4Si4 orders antiferro magnetically below T-N = 136(2)K but its magnetization shows also an anomal y in the temperature range 40-50 K. This last behavior is influenced by the cooling process of the sample. However, neutron diffraction investigation exhibits that U3Cu4Si4 is a collinear antiferromagnet down to 1.5 K with U- magnetic moments (1.20(4) mu(B)) parallel to the c-axis. This magnetic stru cture is discussed in relation to those reported for U3Cu4Ge4 and UCu2Si2 w hich present some structural similarities. (C) 1999 Elsevier Science B.V. A ll rights reserved.