Investigating the role of superdiffusive currents in laser induced demagnetization of ferromagnets with nanoscale magnetic domains.
Understanding the loss of magnetic order and the microscopic mechanisms involved in laser induced magnetization dynamics is one of the most challenging topics in today's magnetism research. While scattering between spins, phonons, magnons and electrons have been proposed as sources for dissipation of spin angular momentum, ultrafast spin dependent transport of hot electrons has been pointed out as a potential candidate to explain ultrafast demagnetization without resorting to any spin dissipation channel. Here we use time resolved magneto-optical Kerr measurements to extract the influence of spin dependent transport on the demagnetization dynamics taking place in magnetic samples with alternating domains with opposite magnetization directions. We unambiguously show that whatever the sample magnetic configuration, the demagnetization takes place during the same time, demonstrating that hot electrons spin dependent transfer between neighboring domains does not alter the ultrafast magnetization dynamics in our systems with perpendicular anisotropy and 140 nm domain sizes.
1] Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay, France [2] Institut Jean Lamour, CNRS UMR 7198, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France.
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Moisan
1] Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay, France [2] Institut Jean Lamour, CNRS UMR 7198, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France.
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Malinowski
Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay, France.
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Mauchain
Institut Jean Lamour, CNRS UMR 7198, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France.
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Hehn
1] Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France [2] CNRS, UMR 7614, LCPMR, 75005 Paris, France.
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Vodungbo
1] Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, 75005 Paris, France [2] CNRS, UMR 7614, LCPMR, 75005 Paris, France.
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Lüning
Institut Jean Lamour, CNRS UMR 7198, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy, France.
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Mangin
Center for Magnetic recording Research, University of California San Diego, La Jolla, CA 92093-0401, USA.
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Fullerton
Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay, France.
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Thiaville