title: Ultrafast optical modification of exchange interactions in iron oxides.
abstract: Ultrafast non-thermal manipulation of magnetization by light relies on either indirect coupling of the electric field component of the light with spins via spin-orbit interaction or direct coupling between the magnetic field component and spins. Here we propose a scenario for coupling between the electric field of light and spins via optical modification of the exchange interaction, one of the strongest quantum effects with strength of 10(3) Tesla. We demonstrate that this isotropic opto-magnetic effect, which can be called inverse magneto-refraction, is allowed in a material of any symmetry. Its existence is corroborated by the experimental observation of terahertz emission by spin resonances optically excited in a broad class of iron oxides with a canted spin configuration. From its strength we estimate that a sub-picosecond modification of the exchange interaction by laser pulses with fluence of about 1 mJ cm(-2) acts as a pulsed effective magnetic field of 0.01 Tesla.
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.|Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: R V
authors.initials: RV
authors.lastname: Mikhaylovskiy
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.
authors.forename: E
authors.initials: E
authors.lastname: Hendry
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Secchi
authors.affiliation: University of Hamburg, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: J H
authors.initials: JH
authors.lastname: Mentink
authors.affiliation: University of Hamburg, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Eckstein
authors.affiliation: Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: A
authors.initials: A
authors.lastname: Wu
authors.affiliation: Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St Petersburg, Russia.
authors.forename: R V
authors.initials: RV
authors.lastname: Pisarev
authors.affiliation: School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, UK.
authors.forename: V V
authors.initials: VV
authors.lastname: Kruglyak
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: M I
authors.initials: MI
authors.lastname: Katsnelson
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: Th
authors.initials: T
authors.lastname: Rasing
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: A V
authors.initials: AV
authors.lastname: Kimel