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New scientific highlight- by MUST PI Richardson
FELs of Europe prize for Jeremy Rouxel- “Development or innovative use of advanced instrumentation in the field of FELs”
Ruth Signorell wins Doron prizefor pioneering contributions to the field of fundamental aerosol science
New FAST-Fellow Uwe Thumm at ETH- lectures on Topics in Femto- and Attosecond Science
International Day of Women and Girls in Science- SSPh asked female scientists about their experiences
New scientific highlight- by MUST PIs Milne, Standfuss and Schertler
EU XFEL Young Scientist Award for Camila Bacellar,beamline scientist and group leader of the Alvra endstation at SwissFEL
Prizes for Giulia Mancini and Rebeca Gomez CastilloICO/IUPAP Young Scientist Prize in Optics & Ernst Haber 2021
Nobel Prize in Chemistry awarded to RESOLV Member Benjamin List- for the development of asymmetric organocatalysis
NCCR MUST at Scientifica 2021- Lightning, organic solar cells, and virtual molecules
#NCCRWomen- NCCR MUST celebrates 50 years women’s right to vote in Switzerland
Kick-Off dynaMENT Mentoring for Women in Natural Sciences- with Ursula Keller as plenary speaker
Four new scientific highlights- by MUST PIs Chergui / Milne / Beaud / Staub, by Wolf / Röthlisberger, by Wörner, and Keller

Photoinduced transitions in magnetoresistive manganites: A comprehensive view

January 31, 2018

Nonthermal control of materials properties: key to developing technologically relevant applications

The excitation of charge-ordered manganites with near-infrared pulses induces a rich dynamical response, including the melting of charge order, the relaxation of structural distortions and the rearrangement of the spins. Using the FEMTO slicing source at SLS, we have studied the structural response during the photoinduced transition in Pr1-xCaxMnO3 thin films. By investigating the dynamics of both superlattice reflections and regular Bragg peaks, we disentangle the different structural contributions and analyze their relevant time-scales. Comparing these results with studies of the charge order and magnetic dynamics, a comprehensive picture of the phase transition is proposed, linked to a single critical fluence fc. For excitations below fc, the charge order and the superlattice are only partially suppressed and the ground state recovers within a few tens of nanosecond via diffusive cooling. When exciting above the critical fluence the superlattice vanishes within approximately half a picosecond followed by a change of the unit cell parameters on a 10 picoseconds time-scale. At this point all memory from the symmetry breaking is lost and the recovery time increases by many orders of magnitude due to the first order character of the structural phase transition. Finally while the melting of the charge order and the disappearance of the superlattice are continuous with fluence, the deformation of the unit cell displays a threshold behavior, which is similar to that found for the emergence of ferromagnetic correlations.

Figure (a) Sketch of the grazing incident geometry at the FEMTO slicing source. (b) Rocking curves of the (002) Bragg reflection at various time delays for a fluence of 8.2 mJ/cm2. (c) Fitted (002) position as a function of time at 100 K (black squares) and 250 K (red dots). At 100 K, the peak shifts towards the high temperature position within 15 ps, evidencing a monoclinic-to-orthorhombic transition.

Reference:  V. Esposito,  L. Rettig, E. Abreu, E. Bothschafter,G. Ingold, M. Kawasaki, M. Kubli, G. Lantz, M. Nakamura, J. Rittman, M. Savoini, Y. Tokura, U. Staub, S. L. Johnson and P. Beaud, Photoinduced transitions in magnetoresistive manganites: A comprehensive view, Phys. Rev. B 97, 014312 (2018). (10.1103/PhysRevB.97.014312) Esposito-2018

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