“…2,[7][8][9] For the system of BaTiO 3 , there have been reports on the electrocoloration, [9][10][11][12][13][14][15] but the authors' main concern was mostly on the origins of color or the correlation of color change to the IR degradation ͑or conductivity change͒ rather than on the mobility itself, thus only a few scattered data on oxygen vacancy mobility are available. 5,6,9,10,13,15 As regards the electrocoloration of BaTiO 3 , it seems to have been generally agreed upon that a brown color emanates from the anode and a blue color from the cathode, 10,11,13 even though there are differences in shade depending on the authors and depending on observation temperatures.…”