Transuranic materials exhibit all types of magnetic behavior. This behavior is a relatively smooth function of atomic number and of the atomic volume of the atoms in the materials. The systematics are best described in terms of these volumes as a measure of intinerancy, mixed valence, or local moment formation.

We discuss chemical trends relating to the formation of heavy electron compounds by uranium. © 1987.

We report high-precision measurements of the upper critical magnetic field of UBe13 as determined from the behavior of magnetic forces and torques acting on our samples. Our results suggest the presence of two sharp features or kinks in the upper critical field as a function of temperature in both single-crystal and polycrystalline samples. We discuss these results in light of recent theoretical and experimental work on the coexistence of heavy-fermion superconductivity with magnetic and/or additional superconducting states. © 1992 The American Physical Society.

Rhodium and platinum have been studied with up to 33% additions of gadolinium. The magnetic properties of the constituents in the layers of a eutectic structure are different from the bulk properties of the constituents. The compound GdPt5 orders ferromagnetically at 13.9 K.

In contrast to the other magnetic Rare Earth (RE) ions for which the cubic Laves REIr2 compound is ferromagnetic, YbIr2 and TmIr2 are antiferromagnetic below 0.40 and 0.05 K, respectively. Both are trivalent above 4 K, with a possible reduced moment for TmIr2 below 0.3 K. In addition, CeIr2 and LuIr2 are superconductive below 0.20 and 0.23 K, respectively. © 1985.

The actinide elements mark the emergence of 5f electrons. The f electrons possess sufficiently unuusual characteristics that their participation in atomic binding often results in dramatic changes in properties. This provides an excellent opportunity to study the question of localization of electrons; a question that is paramount in predicting the physical and chemical properties of d and f electron transition metals. The transition region between localized (magnetic) and itinerant (often superconducting) behavior provides for many interesting phenomena such as sctructural instabilities (polymorphism), spin fluctuations, mixed valences, charge density waves, exceptional catalyic activity and hydrogen storage. This region offers most interesting behavior such as that exhibited by the actinide compounds UBe13 and UPt3. Both compounds are heavy-fermion superconductors in which both magnetic and superconducting behavior exist in the same electrons. The consequences of f-electron bonding (which appears greatest at plutonium) show dramatic effects on phase stability, alloying behavior, phase transformations and mechanical behavior. © 1985.

The superconducting compounds of uranium exhibit a large range of lattice spacings and of electronic specific heat γ values. Recent work has revealed superconductivity to be more common in such systems than formerly believed. © 1985.

We review the experimental results on heavy-fermion uranium based superconductors and magnets. © 1985.

Convincing evidence has been discovered for bulk superconductivity in UPt3 at 0.54 K based on specific-heat, resistance, and ac susceptibility measurements. In addition, new evidence is presented that indicates that UPt3 is a spin-fluctuation system. If true, this is the first coexistent superconductor spin-fluctuation system. © 1984 The American Physical Society.