and 2–2 butoxy ethoxy ethyl acetate). The viscosity of the paste was subject to the printing conditions and the same was main-tained by controlling the amount of organic vehicle in the paste.the preparation of spinel power and formulation thick film pastes andthermistors and its other characterizations were already explainedin detail in our other publications [20–23]. Normally, for IR sensing applications, thermistors with linear dimensions between 0.1 and 10 mm and the resistance value in the range of 0.1–10 M are beingused [5]. Accordingly, the thermistor composition was optimizedto achieve the resistance value of 540 k. Planar thick film ther-mistor of 1 mm × 1 mm dimension was screen printed using thedeveloped thermistor paste composition on to a 1 square inch alu-mina substrate (96%). Pre-fired lead free silver electrodes were usedfor the contact purpose. The printed patterns were dried and subse-quently fired in the four zone thick film firing furnace (BTU make)at 850◦C at dwell of 15 min using the firing profile of 60 min. Thefired film thickness was 25 ± 5 m which was measured by Tallysurf thickness profiler.