Pulsed-laser-deposited polycrystalline/amorphous films of mixed-valent manganites [La0.7Ca0.3MnO3 (LCMO), La0.5Sr0.5MnO3 (LSMO), La0.5Ba0.5MnO3 (LBMO), and (La0.6Pr0.4)0.67Ca0.33MnO3 (LPCMO)] grown at low temperature (450 °C) on single crystal (001) silicon substrate are evaluated for uncooled bolometric applications. It is shown that the temperature coefficient of resistance (TCR) and electrical noise (Sv) depend on the chemical composition. The optimum performance is found for LCMO with TCR of ∼7% K−1 and spectral noise ∼8.9×10−13 V2/Hz. In LBMO and LSMO the noise is much lower, but so is the TCR (1.5%–2% K−1). In LPCMO the TCR is high (∼10% K−1) and the noise is as well.

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Sintered La0.7Sr0.3MnO3 ceramics were prepared by standard solid-state reaction route. Some of these pellets were again heated to 850 °C and quenched to room temperature. These samples were then studied for low-field magnetoresistance (LFMR) effects. Remarkably, upon quenching from high temperature the polycrystalline as well as the crystalline samples are seen to exhibit a dramatic change in LFMR with the emergence of a large positive MR. In the quenched samples a positive LFMR as high as 48% was noted in a field of 200 Oe. This positive MR effect was found to show time-dependent relaxation.