Ultrafast magnetic dynamics in insulating YBa<sub>2</sub>Cu<sub>3</sub>O<sub>6.1</sub> revealed by time resolved two-magnon Raman scattering.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32439836.
- Also identified by DOI 10.1038/s41467-020-16275-9 and PMC identifier 7242324.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Measurement and control of magnetic order and correlations in real time is a rapidly developing scientific area relevant for magnetic memory and spintronics. In these experiments an ultrashort laser pulse (pump) is first absorbed by excitations carrying electric dipole moment. These then give their energy to the magnetic subsystem monitored by a time-resolved probe. A lot of progress has been made in investigations of ferromagnets but antiferromagnets are more challenging. Here, we introduce time-resolved two-magnon Raman scattering as a real time probe of magnetic correlations especially well-suited for antiferromagnets. Its application to the antiferromagnetic charge transfer insulator YBa<sub>2</sub>Cu<sub>3</sub>O<sub>6.1</sub> revealed rapid demagnetization within 90 fs of photoexcitation. The relaxation back to thermal equilibrium is characterized by much slower timescales. We interpret these results in terms of slow relaxation of the charge sector and rapid equilibration of the magnetic sector to a prethermal state characterized by parameters that change slowly as the charge sector relaxes.