Spin dynamics and multipolar ordering in Ce-based heavy-fermion compounds
Heavy-fermion compounds are metallic f-electron systems in which the effective mass of conduction electrons is largely enhanced by interactions with localized magnetic moments of rare-earth or actinide ions. While these systems have been a subject of intense research for the last 40 years, they still continue to reveal interesting new phenomena related to the coexistence of multiple magnetic phases, superconductivity, and orbital ordering. Especially orbital order and the possibility of a meta-orbital transition to tune the ground-state properties came recently into the focus of actual research. From the experimental point of view, a considerable progress has been made as a result of recent developments in the neutron-scattering instrumentation and was largely stimulated by the discovery of new families of heavy-fermion compounds. Among them are, for instance, the Ce-based cubic clathrate systems Ce3Pd20Si6, Ce3Pd20Ge6 or the layered Kondo-lattice system CeCoSi. The former two compounds contain two magnetic ions per unit cell, while the latter is suggested to show a meta-orbital transition under pressure. All these systems display exotic magnetic behavior that you will investigate during your PhD project along with several other Ce-based compounds. The corresponding polycrystalline and single-crystalline samples will be provided from collaborations within MPI CPfS and with the Technical University of Vienna.
You will be using state-of-the-art neutron spectrometers and modern sample environment to measure spin-dynamical properties in single crystals of these materials at ultralow temperatures. In the course of the project you will get hands-on experience with triple-axis and time-of-flight neutron spectrometers, modern cryogenic equipment, as well as various complementary physical methods of sample characterization. Most of the experiments will be performed at external large-scale facilities (neutron sources) worldwide, therefore a willingness to travel is an important prerequisite for this position.