Picosecond Fresnel transmission electron microscopy

Karl B. Schliep, P. Quarterman, Jian Ping Wang, David J. Flannigan

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We report the demonstration of picosecond Fresnel imaging with an ultrafast transmission electron microscope (UEM). By operating with a low instrument repetition rate (5 kHz) and without objective-lens excitation, the picosecond demagnetization of an FePt film, via in situ, femtosecond laser excitation, is directly imaged. The dynamics are quantified and monitored as a time-dependent change in the degree of electron coherence within the magnetic domain walls. The relative coherence of conventional (thermionic) Fresnel transmission electron microscopy is also directly compared to that of Fresnel UEM through the domain-wall size. Further, the robustness and reversibility of the domain-wall dynamics are illustrated by repeating the picosecond image scans at defocus values having the same magnitude but different signs (e.g., +25 mm vs. −25 mm). Control experiments and approaches to identifying and isolating systematic errors and sources of artifacts are also described. This work, and continued future developments also described here, opens the way to direct correlation of transient structure, morphology, and magnetic dynamics in magnetic thin films and spintronic devices.

Original languageEnglish (US)
Article number222404
JournalApplied Physics Letters
Volume110
Issue number22
DOIs
StatePublished - May 29 2017

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 4

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  • Projects

    MRSEC SEED Projects

    11/1/14 → …

    Project: Research project

    University of Minnesota MRSEC (DMR-1420013)

    Lodge, T. P.

    11/1/1410/31/20

    Project: Research project

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