Morphological and magnetic study of CaMnO3-x oxides obtained from different routes

The CaMnO3-x (x = 0 and 0.02) mixed oxide was synthesized from both thermal treatment of the [CaMn(C3H2O4)(2)(H2O)(4)] metallo-organic precursor and ceramic method. In the case of the latter method, temperatures of 1350 degrees C and 50 h were necessary; however, lower temperatures, 800 degrees C, and shorter reaction times, 15 h, were utilized in the attainment of the mixed oxide from the precursor. As a consequence, the morphology of the different products is clearly different. The samples exhibit three-dimensional antiferromagnetic ordering with T-N near 120 K, and a low-dimensional antiferromagnetic ordering at high temperatures. The presence of a ferromagnetic component above T-N was also observed in both compounds, it is slightly stronger in the phase prepared by the ceramic route. (c) 2004 Elsevier Inc. All rights reserved.