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Colloquium: Look for Order in the (Magnetic) Fields, we shall.

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Marcelo Jaime, Los Alamos National Laboratory
When
25 January 2018 from 3:45 PM to 4:45 PM
Where
117 Osmond Laboratory
Contact Name
Jorge Sofo
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The magnetic fields produced in the laboratory are an indispensable tool for understanding and manipulating materials as ground states are directly coupled to the electric charge and magnetic moment of atoms and electrons. The physical properties of most known materials depend weakly on the intensity of applied magnetic fields, and therefore they can be used (as a relatively small perturbation) to determine their fundamental properties, such as energy scales and band structures in metals and insulators. In some materials, however, magnetic fields are coupled strongly and dramatically affect their properties, for example, in quantum Hall effect devices, magnetic materials, multiferroics, and superconductors, members of a class known as strongly correlated systems. For these systems, the magnetic field strength is a thermodynamic parameter as important as pressure or temperature where, very loosely speaking, 1 tesla » 1 degree kelvin.

At the National High Magnetic Fields Laboratory magnetic fields in excess of 100 tesla are used to tune the ground state of correlated systems, and experimentally access rare states of matter in regimes where not the temperature but the magnetic field is the dominant energy scale. Adopting clever approaches to traditional techniques, designed for the microsecond time-scale, we successfully tackle low dimensional and geometrically frustrated quantum magnets, topological Kondo insulator candidates, Lifshitz-type transitions in correlated f-electron metals, and control pathways in ‘hidden order’ compounds. In this Colloquium I will present two recent studies of magnetoelastic correlations, i.e. studies of the crystal lattice as host and witness of field-induced quantum phenomena in the antiferromagnetic Mott insulator UO2, and the antiferromagnetic metal CeRhIn5. In the former, possibly the most studied actinide system ever, we uncover the strongest known piezomagnet with record-high switching fields. [1] These properties are likely a direct consequence of the broken time-reversal symmetry of its non-collinear magnetic ground state. In the later, magnetic fields to 45 tesla are used to reveal a puzzling electronic nematic state that could help build an universal understanding of pressure and magnetic field branches of the (T,H,p) phase diagram. [2] 

 

[1] M. Jaime et al. Nature Communications 8, 99 (2017).

[2] F. Ronning et al., Nature 548, 313 (2017).

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