Ultrafast activation of the double-exchange interaction in antiferromagnetic manganites

Autor: J. R. Hortensius, D. Afanasiev, L. Vistoli, M. Matthiesen, M. Bibes, A. D. Caviglia
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: APL Materials, Vol 11, Iss 7, Pp 071107-071107-6 (2023)
Druh dokumentu: article
ISSN: 2166-532X
DOI: 10.1063/5.0156400
Popis: In doped manganite systems, strong electronic correlations result in rich phase diagrams where electron delocalization strongly affects the magnetic order. Here, we employ a femtosecond all-optical pump-probe scheme to impulsively photodope the antiferromagnetic parent manganite system CaMnO3 and unveil the formation dynamics of a long-range ferromagnetic state. We resonantly target intense charge transfer electronic transitions in CaMnO3 to photodope the system and probe the subsequent dynamics of both charges and spins using a unique combination of time-resolved terahertz spectroscopy and time-resolved magneto-optical Faraday measurements. We demonstrate that photodoping promotes a long-lived population of delocalized electrons and induces a net magnetization, effectively promoting ferromagnetism resulting from light-induced carrier-mediated short-range double-exchange interactions. The picosecond set time of the magnetization, much longer than the electron timescale, and the presence of an excitation threshold are consistent with the formation of ferromagnetic patches in an antiferromagnetic background.
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