Detection of heterogeneities in single-crystal CaCu3Ti4O12 using Conductive Atomic Force Microscopy

This paper reports on a conductive atomic force microscopy (C-AFM) investigation to provide local electrical characterization in a single crystal of CaCu3Ti4O12 (CCTO). The microstructure and dielectric properties were studied and provide evidence for an insulating secondary phase embedded within the semiconducting CCTO matrix. Such insulating electrical heterogeneities cannot be observed with macroscopic measurements such as conventional Impedance Spectroscopy and this study reveals C-AFM to be a powerful tool to assess the electrical homogeneity of semiconducting single crystals such as CCTO.