Fabrication and properties of high B value [Mn1.56Co0.96Ni0.48O4]1−x[SrMnO3]x (0 ≤ x ≤ 0.5) spinel–perovskite composite NTC films

Abstract

The [Mn1.56Co0.96Ni0.48O4]1−x[SrMnO3]x ((MCN)1−x(SM)x, 0 ≤ x ≤ 0.5) ceramic thin composite films were grown on SiO2/Si (100) substrates by the chemical solution deposition (CSD) method. The results of X-ray diffraction showed that the (MCN)1−x(SM)x (0 < x ≤ 0.5) films were a resemblance of the spinel–perovskite composite structure. The field emission scanning electron microscope analyses presented a considerable improvement in relative density with the increasing of the SM contents. In particular, the thermal constant of (MCN)1−x(SM)x ceramic film increased from 3289 to 5390 K with the increasing of the SM contents (x) from 0 to 0.5. This feature was attributed to the increase in the grain boundary resistance and the increase in Mn3+/Mn4+ pairs as the SM contents increased. From the spectroscopic ellipsometer spectroscopy results, it was found that the (MCN)0.5(SM)0.5 film had the biggest refractive index n value of 2.36 at 1.5 eV and a strong absorption peak at 4.0 eV. The sensitivity of MCN spinel ceramic film was enhanced by the compounding of SM. It was a significant disposition in the study of negative temperature coefficient thermistors.