New Member of the Pb-based 1232 Cuprates Containing Boron, (Pb0.5B0.5)Sr2(RE3-x-yCexSry)Cu2Oz (RE = Ho, Tm, and Y)

We previously reported on discovery of new Pb-based 1232 cuprate containing boron in the (Pb0.5B0.5)Sr-2(Er3-x-y Ce (x) Sr (y) )Cu2O (z) system. Recently, a new member of the Pb-based 1232 cuprates containing boron has been synthesized in the (Pb0.5B0.5)Sr-2(RE3-x-y Ce (x) Sr (y) )Cu2O (z) systems (RE=Ho, Tm, and Y). In each system, almost the single 1232 phase samples are found to be obtained for the composition area of x=1.7-1.9 and y=0.2, and the sample with x=1.7 is found to show the smallest resistivity. Despite of annealing under 142 atm O-2 atmosphere at 400 A degrees C for 4 h, the sample with x=1.7 in each system is a semiconductor with the transport process followed by a three-dimensional variable range hopping conduction. Moreover, it is found that the sample with RE=Ho shows magnetic anomalies at two temperatures of about 11 and 16 K, and the sample with RE=Y shows a diamagnetic signal at about 8 K, respectively.