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Proceedings Paper

Colossal magnetoresistive thin films for uncooled bolometer
Author(s): A. Lisauskas; S. I. Khartsev; A. M. Grishin
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Paper Abstract

Pulsed laser deposition technique has been employed to fabricate a continuous series of solid solutions with basic composition of La0.7(Pb1- xSrx)0.3MnO3, which undergo metal-to-insulator transition near the room temperature. These films exhibit colossal magnetoresistivity (CMR) and strong temperature dependence of resistivity in the vicinity of phase transition. Temperature coefficient of resistivity (TCR) has been tailored by precise compositional control tog et maximum value close to room temperature. Film with TCR as high as 7.4%K1 at 295 K and magnetoresistance of 30% at 7kOe has been used to make uncooled bolometer demonstrator. The responsivity as high as 0.6 V/W, noise equivalent power of 3x10-8W/(root)Hz, detectivity of 9x106 cm(root)Hz/W, and noise equivalent temperature difference as low as 120 nK/(root)Hz at 30 Hz frame frequency have been achieved for non-optimized bolometer based on 4.5-micrometers - thick film grown on 2.5x2.5x0.5 mm3 LaAlO3(001) substrate. Measurements of optical responsivity in frequency and time domains yield substrate-to-thermostat thermal conductance G = 3x10-3 W/K and three relaxation times responsible for heat transfer from film thermistor to substrate, from substrate to thermostat, and heat exchange via leads to be 0.5 s, 1.9 ms and 90 microsecond(s) correspondingly. Improving bolometer design by micromachining technique, one can expect that reducing of thermal conductance G down to 10-6 W/K for bolometer with resistance of 500 (Omega) , should result in the increasing of responsivities to 3.9 A/W and 2.8x103 V/W and detectivities to 2.5x108 cm(root)Hz/W and 9.3x108 cm(root)Hz/W at 30Hz in voltage and current biasing regime correspondingly.

Paper Details

Date Published: 8 March 2001
PDF: 6 pages
Proc. SPIE 4318, Smart Optical Inorganic Structures and Devices, (8 March 2001); doi: 10.1117/12.417603
Show Author Affiliations
A. Lisauskas, Royal Institute of Technology (Sweden)
S. I. Khartsev, Royal Institute of Technology (Sweden)
A. M. Grishin, Royal Institute of Technology (Sweden)


Published in SPIE Proceedings Vol. 4318:
Smart Optical Inorganic Structures and Devices
Steponas P. Asmontas; Jonas Gradauskas, Editor(s)

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