A comparative study on the structural, optical, and magnetic behavior of transition metal (Co and Mn) ions substituted Cr2O3 nanoparticles

•The co-precipitation technique has been successfully employed to synthesize Co2+ and Mn2+ substituted Cr2O3 nanoparticles.•XRD and FTIR spectra confirm single phase rhombohedral Co and Mn substituted Cr2O3 nanoparticles.•XPS reveals the mixed oxidation state of Cr, Co, Mn, and oxygen vacancies, which is responsible for the origin of magnetism in as-prepared nanoparticles.•M−T study confirms the dominance of AFM state over FM order below room temperature fitted with Curie-Weiss law and 3D-spin wave model.•M−H recorded at 5 K reveals the coexistence of PM-dominated FM order explained by bound magnetic polarons (BMP).