Synthesis and physical properties of (Cu,M)Ba2Ca3Cu4Oz (M=C,Mg,Ni,Al,Zn,Tl)

We have synthesized the single phase samples of CuxC0.1Ba2Ca3Cu4Oz (x = 0.2 similar to 0.9). Transport and magnetic measurements and iodometric titrat ion analysis were carried out for these materials. From these results we di scuss the correlation between T-c, the Hall number copper valence and oxyge n content. The effect of the substituted M ions on T-c in (CuC, M)-1234 (M = Ni, Zn, Al, Tl, Mg) is also discussed. We propose a unique selective carr ier-doping mechanism in (Cu, C)- and (CuC, Mg)-1234 systems.