Characterization of Textured Ceramics by Electron Paramagnetic Resonance Spectroscopy: I, Concepts and Theory

Electron paramagnetic resonance (EPR) spectroscopy is shown to be a powerful and versatile technique for the detection and characterization of preferred orientation effects in insulating ceramics. While the technique is applicable to both cubic and noncubic ceramics, in this work the conceptual and theoretical basis for the analysis of textured cubic materials is established. The practical utility of the EPR technique is illustrated for the specific case of a paramagnetic impurity (Mn²⁺) in the cubic ceramic MgO. For this example, EPR methods show that texturing occurs in a cold pressed, sintered body and that the preferred orientation corresponds to 〈111〉 axes lying nearly parallel to the direction of the cold-pressing force. The advantages of the EPR technique in characterizing preferred orientation effects in ceramic materials are discussed and compared with more traditional diffraction-based and optical characterization methods.