Mn1.56Co0.96Ni0.48O4±δ flexible thin films fabricated by pulsed laser deposition for NTC applications

• The Mn1.56Co0.96Ni0.48O4−δ (MCN) flexible films are successfully prepared by pulsed laser deposition technique.
• The films changes from amorphous to (1 1 3)-oriented spinel structure as the deposited temperature increases.
• The resistivity, thermistor constant and activation energy are found to decrease dramatically as the grain size increases.
• Higher crystallinity greatly decreased the relaxation frequencies of the flexible films.

Mn1.56Co0.96Ni0.48O4±δ (MCN) thin flexible films are successfully prepared by pulsed laser deposition technique. This study suggests that pulsed laser deposition technique is a great potential candidate for fabricating high-quality MCN flexible thin films. The structure and electrical properties have been investigated as a function of the substrate temperature. The X-ray diffraction, scanning electron microscope and atomic force microscopy analyses show remarkable improvements in crystallinity and grain size for the obtained uniform films. From the electrical experimental results, the resistivity is found to sharply decreases from 3539 to 920 Ω cm. Such feature is attributed to the increase of the grain size with the increase of the substrate temperature. Combined with the analysis of complex impedance spectra, it indicates that when the substrate temperature increases, the relaxation frequencies of the flexible films decreases correspondingly, and the electrical properties are directly relate to distinguish structures of films.

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