Fluence-dependent dynamics of the 5d6s exchange splitting in Gd metal after femtosecond laser excitation

We investigate the fluence-dependent dynamics of the exchange-split 5d6s valence bands of Gd metal after femtosecond, near-infrared (IR) laser excitation. Time- and angle-resolved photoelectron spectroscopy (tr-ARPES) with extreme ultraviolet (XUV) probe pulses is used to simultaneously map the tran...

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Bibliographic Details
Published in:	Japanese Journal of Applied Physics Vol. 55; no. 7S3; pp. 7 - 07MD02
Main Authors:	Frietsch, Björn, Carley, Robert, Gleich, Markus, Teichmann, Martin, Bowlan, John, Weinelt, Martin
Format:	Journal Article
Language:	English
Published:	The Japan Society of Applied Physics 01-07-2016
Subjects:	Dynamics Electron spin Exchange Excitation Femtosecond Lasers Scattering Splitting
Online Access:	Get full text
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Summary:	We investigate the fluence-dependent dynamics of the exchange-split 5d6s valence bands of Gd metal after femtosecond, near-infrared (IR) laser excitation. Time- and angle-resolved photoelectron spectroscopy (tr-ARPES) with extreme ultraviolet (XUV) probe pulses is used to simultaneously map the transient binding energies of the minority and majority spin valence bands. The decay constant of the exchange splitting increases with fluence. This reflects the slower response of the occupied majority-spin component, which we attribute to Elliot-Yafet spin-flip scattering in accordance with the microscopic three-temperature model (M3TM). In contrast, the time constant of the partly unoccupied minority-spin band stays unaffected by a change in pump fluence. Here, we introduce as an alternative to superdiffusive spin transport exchange scattering, which is an ultrafast electronic mechanism explaining the observed dynamics. Exchange scattering can reduce the spin polarization in the partially unoccupied minority-spin band and thus its energetic position without effective demagnetization.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0021-4922 1347-4065
DOI:	10.7567/JJAP.55.07MD02