Flux pinning mechanisms and vortex phase diagram of tin-based inverse opals

Авторы:
Alexey. Anatol’evich. Bykov, D. M. Gokhfeld, Natalya. Evgen’evna. Savitskaya, Konstantin. Yur’evich. Terent’ev, Sergey. Ivanovich. Popkov, Alexander. Mistonov, Natalya. Anatol’evna. Grigor’eva, Anvar. Zakhidov, Sergey. Valentinovich. Grigoriev
Год публикации:
2019
Журнал:
Superconductor Science and Technology
Абстракт:

Three-dimensional periodic tin structures obtained by filling pores of the silicon opals with the sphere diameter of 194 nm (Sn190) and 310 nm (Sn300) were synthesized. The samples were examined by Ultra Small-Angle X-rays Diffraction method, Energy Dispersive X-ray microanalysis and Scanning Electron Microscopy. It was shown that the inverse opal structure consists of octahedral and tetrahedral tin nanoparticles inscribed in opal pores with diameters of 128 nm and 70 nm for the sample Sn300, and 80 nm and 42 nm for the sample Sn190. The study of the magnetic properties of the samples by SQUID magnetometry method showed that the magnetization reversal curves exhibit a hysteresis behavior. As the sizes of tin nanoparticles change, the pinning mechanism of the magnetic flux in the samples is changed. In the sample Sn300 tin nanoparticles behave like classical type-I superconductors. The hysteresis behavior of the magnetization reversal curves in the low magnetic fields for Sn300 is due to the formation of a network of superconducting contours where the magnetic flux is pinned. In the sample Sn190 the octahedral tin nanoparticles are remained the type I superconductors, but smaller tetrahedral particles behave as type-II superconductors. This causes the pinning of the magnetic flux by tetrahedral particles due to the surface barrier and the hysteresis behavior of the magnetization reversal curves in high magnetic fields for Sn190.

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