Neutron spectroscopy in rotating magnetic fields

Experiments performed under continuous rotation of magnetic field direction are becoming routine practice in measurements of thermodynamic or transport properties. Such measurements led to the realization that magnetic phase diagrams of many well known quantum magnets and highly correlated electron systems may show highly nontrivial field-angular dependence. Strong field-angular anisotropy is found not only in the static properties, but also in the excitation spectrum, as we have recently demonstrated for the cubic heavy-fermion compound CeB6 [1]. However, measurements of inelastic neutron scattering in rotating fields are highly ineffective with currently available sample environment.

The goal of the present PhD project is the development and construction of a compact and precise sample rotator for neutron scattering that can operate at low temperatures and be compatible with a conventional cryomagnet. Subsequently, this device will be used for field-angular measurements on existing single crystals of several f-electron compounds of high current interest. This PhD project combines the technical part, consisting in the design and construction of the sample rotator, and the scientific part that involves neutron-scattering measurements at several leading large-scale facilities (research reactors FRM-II near Munich, Germany, and ILL in Grenoble, France). As a result, the method of inelastic neutron scattering will be empowered with a new tuning parameter to explore materials from a new perspective. This new experimental method, combined with the state-of-the-art theoretical models, should offer a sensitive tool to probe spin-orbit interactions and magnetocrystalline anisotropy in a broad range of magnetic systems.

We seek a talented and self-motivated candidate with basic engineering skills and a solid background in condensed matter physics. English writing and communication skills are essential to this project, knowledge of German will be considered a plus. Hands-on experience with diffraction or any other scattering method is desirable. Knowledge of CAD software and/or experience with (micro)mechanical engineering is a plus.

References

[1] P. Y. Portnichenko, A. Akbari, S. E. Nikitin, A. S. Cameron, A. V. Dukhnenko, V. B. Filipov, N. Yu. Shitsevalova, P. Čermák, I. Radelytskyi, A. Schneidewind, J. Ollivier, A. Podlesnyak, Z. Huesges, J. Xu, A. Ivanov, Y. Sidis, S. Petit, J.-M. Mignot, P. Thalmeier, and D. S. Inosov
Field-Angle-Resolved Magnetic Excitations as a Probe of Hidden-Order Symmetry in CeB6
Phys. Rev. X 10, 021010 (2020)

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