Cerium Ferromagnets at the Quantum Critical Point

Florida State University, Tallahassee FL

Investigators

Abstract

Control variables such as chemical composition, applied pressure and applied magnetic field can be used to change the low temperature state of many intermetallic compounds of the element Ce from antiferromagnetically ordered to non-magnetic. This is achieved through lowering the ordering temperature, using a control variable, to T = 0K, the so-called quantum critical point. The realization that the rarely found unconventional superconductivity occurs in many if not all cases in this quantum critical regime now brings to the study of highly correlated electronic materials a focussed avenue for exploring the deep and imperfectly known connection between magnetism and exotic superconductivity, physics strongly implicated in high Tc cuprtate materials. This individual investigator award supports a project that will extend these studies into ferromagnetic Ce materials, allowing exploration of new aspects of the physics involved. The investigation of new materials is a primary experimental strategy in this research, pursuing in particular structure/property correlations - the elusive goal of materials driven physics. In addition to training post doctoral fellows and graduate students in materials driven condensed matter research, undergraduate and high school students will be introduced in the laboratory to condensed matter research through single crystal growth of new materials. The graduate students and postdoctoral fellows involved with this research will gain the experience of performing research at national facilities and laboratories. In addition they will become more globally aware through participation in international collaborations. Almost magnetic metallic materials near absolute zero have properties differing from usual metals. Exotic superconductivity has been discovered in a number of such materials in the neighborhood of this so-called quantum critical point, superconductivity which appears closely associated with the incipient magnetism and which may be closely related to the superconductivity of high Tc cuprates. This individual investigator award supports a research project that will explore cerium ferromagnetic materials across the magnetic/non-magnetic boundary, a class of materials which has been little studied in this connection and which presents new aspects of the physics involved. The goals are to understand the deep tie between unconventional superconductivity and magnetism, learn how to discover new materials which express this physics and extend this understanding into the richer and vaster field offered by new transition metal materials with potential technical applications. Graduate students and post doctoral fellows will be trained how to use the variable of new materials to conduct condensed matter physics research. They will have the experience of performing research at national facilities and laboratories. In addition they will become more globally aware through participation in international collaborations. Undergraduate and high school students will be introduced to condensed matter physics through the synthesis of new materials.