NONVOLATILE FERROELECTRIC SUPERCONDUCTING FIELD-EFFECT TRANSISTOR

A ferroelectric-superconducting three-terminal device consisting of a YBa2Cu3O7-x (YBCO) base layer and a PbZrTiO3 (PZT) gate has been fabri cated which acts as a ferroelectric-superconducting field effect trans istor (FSuFET). The PZT/YBCO layers were deposited sequentially on an MgO (100) substrate by excimer laser deposition. The thickness of the YBCO layer was nominally 100nm and that of the PZT layer was 500nm. Bo th conventional DC measurements and a modified admittance spectroscopy method were used to characterize the device. The YBCO channel resista nce has been shown to be modulated by over 25% dependent on the polari zation of the PZT gate, the highest modulation shown to date. The pola rization state and thus the channel state were retained for greater th an 10(6) seconds. This was the first demonstration of non-volatility i n such a superconducting logic device. The transient behavior of the f erroelectric-superconducting device has also been studied and shows fo ur-state characteristics. The four states can be controlled by changin g the PZT polarization state or switching of the YBCO channel from the superconducting state to the normal state.