Structure and Transport Studies on PrBa₂(Cu_1-xM_x)₃O₇: M = Al, Fe, and Ni

Abstract

We have fabricated metal doped PrBa 2 Cu 3 O 7 (PBCO), i.e. PrBa 2( Cu 1-x M x)3 O 7 (PBCMO) with M = Al , Fe, and Ni, and x = 0.05, 0.10, 0.15, and 0.20. X-ray data indicate no significant second phase for Ni-doped samples until 15% doping level is reached. No second phase was found in Al- and Fe-doped samples up to the 20% doping level. All the doped samples are in orthorhombic structure and their lattice parameters are very close to those of YBa 2 Cu 3 O 7-δ (YBCO). However, for Al or Fe doped samples the difference in lattice parameters a-b has decreased from that of PBCO. At 77 K the electrical resistivity for Al- or Fe-doped samples is several orders in magnitude higher than that of PBCO. Therefore these compounds may be better buffer-layer materials for YBCO superconducting electronic circuits and devices.

Fabrication,Transport and Raman Studies of Pulsed Laser Deposited Al/Ga Doped PBCO Thin Films

“…At 77 K, Al doped ceramic PBCO showed about four orders in magnitude higher electrical resistivity than in undoped PBCO [1,4]. In our previous experiments, we reported the fabrication of pure phase PrBa 2 (Cu 1-x M x ) 3 O 7 (PBCMO, M=Al, Ga, Co, Ni, Zn and Fe; x=0.05, 0.10, 0.15, 0.20) bulk materials.…”

“…The excellent lattice match reduces the strain of the YBCO film in the S-I-S junction and thus preserves its high T c . Experiments, however, show that the resistivity of the ceramic PBCO at 77 K is only about 200 Ω-Cm [2,4], which will be much smaller for thin films and thus can not provide a sufficient potential barrier for a YBCO S-I-S junction at 77 K. Proximity effect has also been observed in PBCO when in contact with YBCO which deteriorates the insulating property in YBCO/PBCO multilayer [1]. Experiments, however, show that the resistivity of the ceramic PBCO at 77 K is only about 200 Ω-Cm [2,4], which will be much smaller for thin films and thus can not provide a sufficient potential barrier for a YBCO S-I-S junction at 77 K. Proximity effect has also been observed in PBCO when in contact with YBCO which deteriorates the insulating property in YBCO/PBCO multilayer [1].…”