Spin fluctuations in itinerant electron systems

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NON-TECHNICAL ABSTRACT: While a century old problem, magnetism remains poorly understood. Of the two extreme magnetic states - those with magnetic moments localized in small spatial volumes (local moments) and those shared by the entire compound (itinerant moments), the former remains better described theoretically, with most real materials actually residing in the continuum between the two. The main goal of this project is to discover and characterize novel itinerant magnets without magnetic elements. It is of particular interest to understand what happens as the temperature is lowered close to absolute zero, or towards quantum phase transitions (QPT), fundamentally distinct transitions compared to the more familiar phase transitions, for example liquid-to-solid. Exotic physics is believed to emerge from QPTs and these will be studied with tuning parameters such as composition, pressure or magnetic field. Undergraduate and graduate students involved in the project will be trained in crystal growth and characterization, valuable tools for materials driven condensed matter research. The PI will develop a class on scientific presentation skills, and will establish two series of lab open houses, for hands-on experience for children and for adults.TECHNICAL ABSTRACT: This NSF award supports experimental investigations and education in condensed matter physics, with focus on novel magnetic states of matter in the itinerant moment regime. In particular, the goal of this proposal is to investigate novel itinerant magnets containing no magnetic elements, where the the chemical tunability of the only three known such magnetic systems will be explored towards designing the new compounds of interest. The main thrusts of the project are studies of (i) the correlations between the structural and physical properties of itinerant electron magnets, (ii) the interplay between electronic and magnetic ground states and (iii) non-Fermi liquid behavior in itinerant magnet systems. In addition, the recently discovered hardness of some related alloys will be investigated and the materials optimized for medical and possibly new technological applications. The PI will develop a class on scientific presentation skills, and will establish two series of lab open houses, for hands-on experience for children and for adults.