Magnetic properties of UCuGa and U2CuGa3 by AC-magnetic susceptibility and neutron diffraction

✍ Scribed by V.H. Tran; D. Kaczorowski; T. Roisnel; R. Troć; H. Noël; F. Bourée; G. André

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 501 KB
• Volume: 205
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)00162-o

✦ Synopsis

The uranium intermetallics UCuGa and U2CuGa3 have been studied by means of neutron diffraction and AC-, DC-magnetic susceptibility measurements. UCuGa crystallizes either in the hexagonal LiGaGe-type (space group P63mc) or in the Caln2-type structure (P/63mmc), whereas U2CuGa3 belongs to the slightly different hexagonal structure of Lu2CoGaa-type (P/63mmc). Below TN = 30K, UCuGa shows a collinear antiferromagnetic ordering which corresponds to a double-sized orthorhombic cell with k = (0,1/2, 0). The uranium magnetic moments are parallel to the b-axis of the crystal unit cell with a value of (1.27 + 0.06)#B at 1.3 K. Such a magnetic structure is consistent with a two-dimensional X-Y magnetic moment system. For U2CuGa3 no magnetic transition can be detected by neutron diffraction. Indeed, magnetic susceptibility experiments show that its magnetic behaviour could be interpreted on the basis of spin-glass properties.