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Title: Ultrafast Magnetism Dynamics Measure Using Tabletop Ultrafast EUV Sources

In our work to date, we made two significant advances. First we demonstrated element-selective demagnetization dynamics for the first time, with a record time resolution for x-ray probing of 55 fs. Second, in new work, we were able to probe the timescale of the exchange interaction in magnetic materials, also for the first time. Our measurements were made using the transverse magneto-optic Kerr effect (T-MOKE) geometry, since the reflectivity of a magnetic material changes with the direction of the magnetization vector of a surface. In our experiment, we periodically reversed the magnetization direction of a grating structure made of Permalloy (Ni80Fe20) using an external magnetic field. To achieve maximum contrast, we used HHG light spanning the M-shell (3p) absorption edges of Fe and Ni. Our characterization of the static magnetization of a Permalloy sample shows high magnetic asymmetry at photon energies just above and below the absorption edges at 55 eV and 65 eV, respectively. This result is in excellent agreement with measurements done on the same using a synchrotron source.
Authors:
 [1] ;  [2]
  1. NIST
  2. University of Colorado
Publication Date:
OSTI Identifier:
1090757
Report Number(s):
DOE-NIST-01480
DOE Contract Number:
SC0001480
Resource Type:
Technical Report
Research Org:
National Institute of Standards and Technology (NIST)
Sponsoring Org:
USDOE; USDOE SC Office of Basic Energy Sciences (SC-22)
Contributing Orgs:
NIST, University of Colorado/JILA
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY