Two-component heat diffusion observed in LaMnO3 and La0.7Ca0.3MnO3
Artikel i vetenskaplig tidskrift, 2010

We investigate the low-temperature electron, lattice, and spin dynamics of LaMnO3 (LMO) and La0.7Ca0.3MnO3 (LCMO) by resonant pump-probe reflectance spectroscopy. Probing the high-spin d-d transition as a function of time delay and probe energy, we compare the responses of the Mott insulator and the double-exchange metal to the photoexcitation. Attempts have previously been made to describe the subpicosecond dynamics of colossal magnetoresistance manganites in terms of a phenomenological three-temperature model describing the energy transfer between the electron, lattice, and spin subsystems followed by a comparatively slow exponential decay back to the ground state. However, conflicting results have been reported. Here we first show clear evidence of an additional component in the long-term relaxation due to film-to-substrate heat diffusion and then develop a modified three-temperature model that gives a consistent account for this feature. We confirm our interpretation by using it to deduce the band gap in LMO. In addition, we also model the nonthermal subpicosecond dynamics, giving a full account of all observed transient features both in the insulating LMO and the metallic LCMO.

Författare

Johan Bielecki

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Ralf Rauer

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Ezio Zanghellini

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Robert Gunnarsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

K. Dorr

Leibniz-Institut fur Festkorper- und Werkstoffforschung Dresden

Lars Börjesson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Physical Review B - Condensed Matter and Materials Physics

1098-0121 (ISSN)

Vol. 81 6 art. no. 064434- 064434

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1103/PhysRevB.81.064434