Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 26: Oxides

DS 26.6: Talk

Thursday, March 29, 2007, 16:15–16:30, H34

Ag-doped LaPbMnO₃ thin films and laser induced thermoelectric voltages — •Pengxiang Zhang^1,2, Songlin Tan², Hui Zhang², and Hanns-Urlich Habermeier¹ — ¹Max-Planck Institut for Solid State Research, Stuttgart, D-70569 — ²IAMPE, KUST, Kunimng, China 650051

Ag-doped LaPbMnO₃ thin films were grown on vicinal cut substrates by PLD technique. Laser induced voltages were measured for the first time in these thin films. It was proved that the laser induced voltages are due to the anisotropic thermoelectric effect, similar to that observed in YBa₂Cu₃O₇ by Chang et al in 1990 and that in LaCaMnO₃ by H.-U. Habermeier et al in 1998. It was found that with increasing Ag-doping from 0 to 10 wt%, the laser induced thermoelectric voltages (LITV) are firstly increased and then reduced, while the FWHM (to) of the time response of the induced voltages become smaller than that of pure LaPbMnO₃ thin film, and demonstrate a minimum at 6 wt% of Ag-doping. Defining a figure of merit (Fm) for the performance of LITV devices used in pulsed laser detection: Fm = Up/to, where Up is the peak value of LITV, it was found that 6 wt% Ag-doping sample shows a maximum Fm. The short time response of the Ag-doped LaPbMnO₃ thin films in LITV was explained by the increased electric conductivity, hence the higher thermo-conductivity in these thin films.