Structural studies of spinel manganite ceramics with positron annihilation lifetime spectroscopy

The new transition-metal manganite Cu_0.1Ni_0.8Co_0.2Mn_1.9O₄ ceramics for temperature sensors with improved functional reliability are first proposed. It is established that the amount of additional NiO phase in these ceramics extracted during sintering play a decisive role. This effect is well revealed only in ceramics having a character fine-grain microstructure, while the monolithization of ceramics caused by great amount of transferred thermal energy reveals an opposite influence. The process of monolitization from the position of evolution of grain-pore structure was studied in these ceramics using positron annihilation lifetime spectroscopy.