Study of the electric hysteresis loop from properties of the Bi-O2 layer on the cleaved surface of a Bi2Sr2CaCu2Oy single crystal

✍ Scribed by Xiaolin Wang; Zhuo Wang; Hong Wang; Minhua Jiang

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 313 KB
• Volume: 208
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90197-x

✦ Synopsis

The electric hysteresis loop of a Bi~Sr2CaCu2Oy (BSCCO) single crystal was measured at high frequency at room temperature in air and at 77 K in liquid nitrogen to determine whether the BSCCO superconductor has ferroelectricity. It has been found that the cleaved plate-like crystals have a hysteresis loop under low external voltage. However, it can be destroyed together with the formation of a insulating layer on the sample local surface around the electrode at a certain high external voltage. And the single crystal also shows a hysteresis loop at 77 K in liquid nitrogen in spite of the superconducting state of the sample. Based on some detailed results, it is conducted that the BSCCO superconductor has no ferroelectricity. The formation of the hysteresis loop arises from semiconducting properties of the surface state of the Bi-O2 layer which is revealed on the single crystal surface, rather than the bulk behavior of the sample. Furthermore, the superconducting electron is in the Cu-O2 network and the difference between properties ofth Bi-O2 layer in the superconducting state and in the normal state are emphasized in this paper.