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Two-component heat diffusion observed in LaMnO3 and La0.7Ca0.3MnO3

Johan Bielecki (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; Ralf Rauer (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; Ezio Zanghellini (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; Robert Gunnarsson (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; K. Dorr ; Lars Börjesson (Institutionen för teknisk fysik, Kondenserade materiens fysik)
Physical Review B (1098-0121). Vol. 81 (2010), 6, p. art. no. 064434.
[Artikel, refereegranskad vetenskaplig]

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.

Denna post skapades 2010-03-23. Senast ändrad 2016-08-18.
CPL Pubid: 118288


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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kondenserade materiens fysik (1900-2015)
Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik


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Chalmers infrastruktur

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