DQMP Seminar - Prof. Siân E Dutton - University of Cambridge

02.09.2025 14:00 – 15:15

Structure and functionality in complex oxides
Siân E Dutton, University of Cambridge
https://duttongroup.weebly.com/

Research in the Dutton group focuses on the synthesis and characterisation of functional energy materials. In this talk I will present some of our recent results on our work on cathodes for Na-ion batteries and low temperature magnetocalorics.
NaNiO2, and solid solutions with it as an end-member, have been studied as a Na-ion battery cathode, and it adopts a similar structure to other battery materials LiNiO2, α-NaMnO2, and LiMnO2. In this talk In the stoichiometric system. I will present our study of the local structure and how this provides experimental evidence for a displacive Jahn-Teller transition on heating comparing it to the Jahn-Teller transition in LaMnO3. I will then show our work determining the structures of the NaxNiO2 (x=2/3, 1/2, 2/5, 1/3) phases formed on electrochemical cycling, discussing the role of Na-vacancy, Ni-charge and Jahn-Teller ordering on the structures adopted. The results will be compared to other layered transition-metal oxides with Jahn-Teller active ions and how this might inform doping strategies for cathodes presented.
Magnetic cooling relies on the magnetocaloric effect (MCE) where a change in the entropy on application of a magnetic field drives cooling during an adiabatic demagnetisation process. At low temperatures magnetic cooling is currently achieved using dilute magnetic salts with low magnetic ordering temperature. In this talk I will present recent work exploring complex oxides for solid state magnetic cooling applications. I will focus on our work exploring rare earth double perovskites, A2GdMO6 (A=Ba, Sr, Ca, M=Sb, Nb), which form a fcc lattice of magnetic Gd3+ ions. In these materials magnetic measurements indicate weak magnetic interactions and the magnetocaloric effect is well described using a free-spin model of non-interacting spins. I will introduce the mixed-metal Ba2GdNb1-xSbxO6 solid solution and discuss how substitution on non-magnetic ions can tune the magnetic properties, enhancing the MCE.

Siân Dutton is a Professor in Physics and Solid State Chemistry at the Cavendish Laboratory in the University of Cambridge and Director of the Winton Programme for the Physics of Sustainability. Siân completed her DPhil. on the ‘Synthesis and Characterisation of Mixed Metal Oxides’ under the supervision of Prof. Peter Battle. She then moved to Princeton University for postdoctoral work with Prof. Bob Cava on geometrically frustrated magnets. Since 2012 Siân has been based at the Cavendish Laboratory first as a Winton Advanced Research Fellow, and subsequently as a University Lecturer (2015) and Reader (2018). Her multidisciplinary research group explores the relationships between composition, structure, and physical properties with a focus on energy materials, including materials for rechargeable batteries, hybrid perovskites and low temperature magnetocalorics.

Organisé par : Prof. von Rohr

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückeberg

entrée libre

Fichiers joints

image.png

21 Kb