Angular dependence of the high-frequency vortex response in YBa₂Cu₃O_7?x thin film with self-assembled BaZrO₃ nanorods

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• 作者：N. Pompeo ; R. Rogai ; K. Torokhtii ; A. Augieri ; G. Celentano ; V. Galluzzi ; E. Silva
• 关键词：YBCO ; BaZrO3 nanorods ; Surface impedance ; Vortex dynamics ; Angular dependence
• 刊名：Physica C
• 出版年：2012
• 出版时间：September, 2012
• 年：2012
• 卷：479
• 期：Complete
• 页码：160-163
• 全文大小：458 K

文摘

We present a microwave study of the angular dependence of the flux-flow resistivity ¦Ñ_ff and of the pinning constant k_p in YBCO thin films containing BZO nanorods. We find that BZO nanorods are very efficient pinning centers, even in tilted fields. We find that ¦Ñ_ff is a scaling function of a reduced field H/f(¦È). We extend a model for the anisotropic motion of vortices in uniaxially anisotropic superconductor, able to describe the experimental f(¦È) on the basis of only the intrinsic anisotropy of YBCO. The pinning constant k_p, by contrast, exhibits different field dependences in different angular ranges, consistent with pinning by BZO at angles as large as 60¡ã, and with pinning along the a,b planes as originating from the same mechanism as in pure YBCO with the field along the c axis.