Epitaxial manganite freestanding bridges for low power pressure sensors.

The highly temperature-dependent resistivity of the La2/3Sr1/3MnO3 (LSMO) manganite is taken as an advantage in a pressure sensor design based on the Pirani effect. Thin epitaxial films are grown on silicon substrate thanks to a SrTiO3 buffer layer that allows the fabrication of freestanding bridges by means of clean-room processes. The devices are then heated by Joule effect and their temperature modulated by heat transfer through the surrounding gas. The higher the current flowing in the bridge, the larger the resistance variation with pressure is, due to the Pirani effect. The heating current and device geometry are tuned in order to stay in a monotonous regime, avoiding the change of sign of the LSMO temperature coefficient. A sensitivity increased by a factor of 3 and a power consumption reduced by 5 orders of magnitude are measured by comparing oxide devices with conventional metallic ones of same geometry. [ABSTRACT FROM AUTHOR]