Compositions of transition metal manganites in the form of particles or ceramics, their preparation and their use in the production of thermistors

摘要

A manganite type composition of the formula Mn3-x-y-zNixCoyMzO4 (I) wherein M is at least one metal selected from Cu, Zn and Cd, y and z range from 0 to 1, and (x+y+z) is lower than 2. This composition can also contain a doping agent. The composition is either a particulate composition wherein at least 90% of the particles have a regular form and a size lower than 5 mu M or a ceramic material having a density greater than 94% of the theoretical density. The composition is useful in the production of thermistors.