Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics

•Mn:ZnO ceramics were prepared by solid-state reaction method.•Defects (oxygen vacancies) was introduced in system via heat treatments under reducing atmosphere.•Structural characterization was used to evaluate the nature of the defects and the Mn incorporation into the ZnO lattice.•We identify the that the Mn incorporation takes place mainly at the surface of the ZnO grains.•Magnetic data reveal that, in spite of the oxygen vacancies, the samples present only a Curie-Wiess paramagnetic behavior.