138 research outputs found
Fluence dependent femtosecond quasi-particle and Eu^{2+} -spin relaxation dynamics in EuFe_{2}(As,P)_{2}
We investigated temperature and fluence dependent dynamics of the time
resolved optical reflectivity in undoped spin-density-wave (SDW) and doped
superconducting (SC) EuFe(As,P) with emphasis on the ordered
Eu-spin temperature region. The data indicate that the SDW order
coexists at low temperature with the SC and Eu-ferromagnetic order.
Increasing the excitation fluence leads to a thermal suppression of the
Eu-spin order due to the crystal-lattice heating while the SDW order is
suppressed nonthermally at a higher fluence
Ultrafast photoinduced phase separation dynamics in Pr(0.6)Ca(0.4)MnO(3) thin films
The time resolved Magnetooptical Kerr effect in the substrate-strain-induced
insulating ferromagnetic phase in (PrCa)MnO thin films on
two different substrates was measured in a magnetic field up to 1.1T. The
photoinduced Kerr rotation and ellipticity show remarkably different
magnetic-field dependence. From the comparison of the magnetic field
dependencies of the photoinduced and static Kerr rotation and ellipticity we
conclude that a transient ferromagnetic metallic phase, embedded within the
insulating ferromagnetic phase, is created upon the photoexcitation at low
temperatures. A comparison of temporal dependence of the photoinduced Kerr
signals with the photoinduced reflectivity indicates the change of the
fractions of the phases takes place on a timescale of ten picoseconds
independent of the substrate.Comment: accepted in EP
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