Electrical and noise properties of YBa/sub 2/Cu/sub 3/O/sub 7/ ramp-type Josephson junctions

Josephson junctions with PrBa/sub 2/Cu/sub 3/O/sub 7/ barriers are used in integrated magnetometers, where for biomagnetic applications the noise at low frequencies should be as low as possible. The 1/f-noise contribution close to the critical current is governed by critical current fluctuations. We measure the electrical and noise properties of our ramp-type Josephson junctions and interpret them in a model of resonant tunneling through the PrBa/sub 2/Cu/sub 3/O/sub 7/ barrier. We find that the critical current fluctuations /spl delta/I/sub c//I/sub c/ scale with the temperature dependent critical current. The consequences for the noise properties of integrated magnetometers are discussed.