“…Internal or surface barrier layer capacitance effects have been indicated as the origin of the high effective permittivity of this material (Subramanian et al, 2000, Sinclair et al, 2002, Prakash and Varma, 2006, Krohns et al, 2008, Ramirez et al, 2009, Schmidt et al, 2012, Thongbai et al, 2013. Similar properties have been found for some new, CaCu 3 Ti 4 O 12 -relative compounds, such as Bi 2/3 Cu 3 Ti 4 O 12 (Liu et al, 2004, Szwagierczak, 2009, Szwagierczak and Kulawik, 2012, Tan et al, 2010, ACu 3 B 4 O 12 (with A ϭ alkali, alkaline earth or rare earth; B ϭ Ru, Ti) (Ebbinghaus et al, 2009), Cu 2 Ta 4 O 12 (Ebbinghaus, 2007, Renner et al, 2004, Szwagierczak and Kulawik, 2008) and A 2/3 CuTa 4 O 12 (Szwagierczak and Kulawik, 2010, Szwagierczak, 2012.…”