Seminar: Element specific insights into solids for magnetic refrigeration

Due to climate change, population growth and increasing expectations regarding quality of life, the demand for energy for cooling processes is growing much faster worldwide than for heating. Another issue with today's refrigeration systems is that most coolants are harmful to the environment and to health. A novel technology could provide a solution: magnetic refrigeration. The magnetocaloric effect (MCE) is key to solid-state refrigeration. In this talk, I will present an element-specific understanding of hysteresis in magnetocaloric materials at the atomic level. This is achieved through studies combining X-ray absorption spectroscopy (XAS) and nuclear resonance inelastic X-ray scattering (NRIXS) at synchrotron radiation facilities, as well as laboratory-based Mössbauer spectroscopy investigations. These techniques enable us to correlate changes in electronic structure, magnetic spin and orbital moments, local atomic structure, and vibrational density of states along (structural) phase transitions [1–6]. Our experiments bridge the gap between efforts to synthesise new functional magnetocaloric materials and theoretical work aiming at an atomistic understanding of these systems.

[1] O. N. Miroshkina et al., Phys. Rev. B 106, 214302 (2022)
[2] A. Aubert et al., IEEE Trans. Instrum. Meas. 71, 1-9 (2022)
[3] R. Nadarajah, Sci. Rep. 11, 13719 (2021)
[4] W. Griggs et al., APL Mater. 8, 121103 (2020)
[5] A. Terwey et al., Phys. Rev. B 101, 064415 (2020)
[6] J. Landers et al., Phys. Rev. B 98, 024417 (2018)