A new technique for measuring the microwave penetration depth in high-Tc superconducting thin films

✍ Scribed by Bekir Aktaş; Hüseyin Zafer Durusoy

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 398 KB
• Volume: 260
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(96)00114-1

✦ Synopsis

The electron spin resonance (ESR) technique has been used to obtain the microwave (MW) penetration depth of YBa2Cu307 thin films. An ESR-signal-generating marker was placed in between two high-temperature superconducting (HTSC) films to probe the MW field penetrating through the films. Below the superconducting transition temperature (T~) the HTSC film started to screen the marker inside the sandwich. A meaningfully diminishing ESR signal was reproducibly recorded for various samples with different markers such as paramagnetic diphenyl pierylhydrazy (DPPH), Mn ++ impurity in MgO and a ferromagnetic (FM) permalloy film. The temperature dependence of the ESR signal intensity above and below T c has been studied to deduce the penetration depth from the measured signal intensity. A very rapidchange of A just below T c, slowed down later at lower temperatures and became smoothly changing. The value hab = 1020 A has been measured for c-axis films at 77 K.