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Effect of heat treatment on nickel manganite thin film thermistors deposited by electron beam evaporation

Parlak, Mehmet
Hashemi, T.
Hogan, M.J.
Brinkman, A.W.
Thin ®lms of nickel manganite were deposited onto different substrates by means of electron beam evaporation from a powder source of the compound and annealed at 500 and 6008C for 30 min. in air, oxygen or nitrogen to study the effects of annealing temperature and atmosphere on the structure and properties of grown thin ®lms. X-ray diffraction and infrared spectroscopy were used to con®rm the formation of nickel manganite; the integrity of the ®lms and their elemental compositions were assessed using a scanning electron microscope equipped with an energy dispersive X-ray analyser. Resistance±temperature characteristics were measured between room temperature and 600 K. The values of thermistor constant (B) were found to be dependent on the post growth treatments; annealing in O2 or air yielded the lowest values of B , 2000±3000 K, while as-deposited and N2 annealed layers had values of B , 5000±6500 K. q 1999 Elsevier Science S.A. All rights reserved.