ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarPenc KarloHUN-REN Wigner RCP SZFINegative thermal expansion in 
the plateau state of a magnetically-frustrated spinelThursday, 6 March 2025, 
10:00, KFKI Campus, Bldg. 1, 2nd floor, Conference RoomCdCr2O4 is a 
frustrated magnetic insulator featuring a large one-half magnetization 
plateau. The plateau arises from lattice deformations that relieve 
frustration, which can be seen experimentally through magnetostriction. On 
the experimental side, dilatometry provides a precise phase diagram in a 
magnetic field of up to 30 Tesla [Rossi et al., Phys. Rev. Lett. 123, 027205 
(2019)]. These measurements found a significant negative thermal expansion 
associated with the collinear half-magnetization plateau for magnetic fields 
above 27 Tesla. By comparing experiments with theoretical models, we find 
that this negative thermal expansion comes from a sharp, 
temperature-dependent drop in magnetization caused by nearly localized spin 
excitations in the plateau phase. Finally, I discuss how these findings may 
lead to a magnetocaloric effect. Minden érdeklődőt szívesen látunk! - 
Everyone is welcome to attend.Attila Nagysem-admin AT szfki.hu