Magnetic correlations reflected by anomalies in transport and elastic properties of uranium intermetallics

• Published in: Physica. B, Condensed matter Condensed matter, 2003-04, Vol.328 (1), p.95-99
• Main Authors: Sechovský, V., Honda, F., Janoušová, B., Prokeš, K., Svoboda, P., Syshchenko, O., Andreev, A.V.
• Format: Article
• Language: English
• Subjects: Antiferromagnetic correlations; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical resistivity; Entropy changes; Exact sciences and technology; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect, magnetic cooling; Physics; Saturation moments and magnetic susceptibilities; Short range antiferromagnetic order; Thermal expansion; UTX compounds
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(02)01817-3

We discuss anomalies in temperature dependences of the electrical resistivity ρ( T) and thermal-expansion Δ L/ L( T) observed for UTX compounds (T=transition metal, X=p-electron element) in paramagnetic range. We shall concentrate on the antiferromagnets UNiAl and UNiGa and the itinerant 5f-electron metamagnet UCoAl. The ρ(T) and Δ L/ L(T) anomalies are usually strongly anisotropic and survive far above the Néel temperature or a characteristic temperature T * (UCoAl) but can be removed in a high magnetic field applied along the easy-magnetization direction ( c-axis). In some cases, the available specific-heat data allow to calculate the entropy change Δ S connected with applying a high magnetic field along the c-axis. The Δ S values also show a maximum above T N (UNiAl, UNiGa) or T * (UCoAl) and then slowly decay with increasing temperatures. A possible scenario for these phenomena presented here, is based on existence of antiferromagnetic (AF) correlations and/or short-range AF ordering surviving in paramagnetic range.