The dielectric hysteresis of YBCO-SrTiO₃-YBCO structures at 4.2 K

Abstract

The dielectric hysteresis (DH) of structures based on the single crystal SrTiO₃ is the stable change of initial structure capacitance after the bias voltage influence. Experimental research of DH were carried out with the different conditions on the contact electrode—SrTiO₃; the temperature dependence of resistivity of this superconducting were also measured.

Just after preparing of YBCO films DH was absent, then it appeared in 10₃ hours and reached the values ΔC/C _o up to 0.6-0.7 in the electric fields with the average value 10⁵ V/m, and beside the structure capacitance increased. During this time the p(T) dependence of electrodes was not changing.

DH absence in structures YBCO-SrTiO₃-YBCO is likely to be connected with the change of work function of SrTiO₃ (5.4 eV), of normal metal (4.3-4.6 eV) and of YBCO (5.2-6.2 eV). The possible mechanisms of DH formation in the course of time are discussing.

Key Words:

• dielectric hysteresis
• HTSC films
• nonlinear dielectric
• oxygen ion moving
• strontium titanate