Maj. Verhoeven et al., RAMP-TYPE JUNCTION PARAMETER CONTROL BY GA DOPING OF PRBA2CU3O7-DELTABARRIERS, Applied physics letters, 69(6), 1996, pp. 848-850
We analyzed the transport of charge carriers across PrBa2Cu3-xGaxO7-de
lta (PBCGO) barriers as a function of barrier thickness, Ga-doping lev
el, temperature, and bias voltage. It was found that by Ga doping, the
normal state resistance (R(n)) of the junctions was systematically in
creased, while the critical current (I-c) remained constant. We argue
that pair transport takes place by direct tunneling, whereas the quasi
particles have access to channels formed by one or more localized stat
es inside the barrier. By Ga doping the I(c)R(n) products were increas
ed, up to 8 mV at 4.2 K for junctions with 8 nm thick PrBa2Cu2.6Ga0.4O
7-delta barriers. (C) 1996 American Institute of Physics.