Here we report on the preparation and structural, magnetic and electrical characterization of BiFeO 3 and Bi 0.9 Ca 0.1 FeO 3 ceramic multiferroic samples. We suggest that Ca-doping creates oxygen vacancies and destabilizes the BiFeO 3 spiral magnetic structure. We also study resistive switching effects in Bi 0.9 Ca 0.1 FeO 3 with metallic electrodes, finding that the appearance of the effect is dependant on the fabrication procedure of the metallic electrode. On the basis of these observations, we critically revise some assumptions in currently available models of resistive switching of complex oxides.