Fabrication and properties of Mn1.56Co0.96Ni0.48O4 free-standing ultrathin chips

Mn1.56Co0.96Ni0.48O4 (MCN) free-standing ultrathin chips are successfully fabricated by using screen printing. The structure, electrical and IR absorption properties have been investigated as a function of the sintering temperature. The X-ray diffraction, X-ray photoelectron spectroscopy and field emission scanning electron microscope analyses show remarkable improvements in crystallinity, stoichiometry and relative density for MCN chips. From the electrical experimental results, it is found that the resistivity of the chip samples sharply decreases from 2660 to 21.9 Ω cm. Such feature is attributed to the decrease in the grain boundary resistance and the increase in Mn3+/Mn4+ ratio with increasing sintering temperature. Furthermore, Fourier transform infrared spectra show that the absorption bands ν1 (around 1160 cm−1) at 1100 °C almost disappears while the others still remain. It is ascribed to the increase in the density of samples. The intensities of symmetry bands ν2 (850 cm−1) are also found to be consistent with an increase in ratio of Mn3+ to Mn4+ ions with increasing sintering temperature.