Direct Observation of Vortices and Antivortices Generation in Phase-Separated Superconductor Sn-Pb Solder

Fuente: arXiv
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Autores principales: Arima, Hiroto, Murakami, Takumi, Kinoshita, Yuto, Sepehri-Amin, Hossein, Tokunaga, Masashi, Nojima, Tsutomu, Mizuguchi, Yoshikazu
Formato: Preprint
Publicado: 2025
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author Arima, Hiroto
Murakami, Takumi
Kinoshita, Yuto
Sepehri-Amin, Hossein
Tokunaga, Masashi
Nojima, Tsutomu
Mizuguchi, Yoshikazu
author_facet Arima, Hiroto
Murakami, Takumi
Kinoshita, Yuto
Sepehri-Amin, Hossein
Tokunaga, Masashi
Nojima, Tsutomu
Mizuguchi, Yoshikazu
contents Quantized vortices in type-II superconductors provide insights into the mechanisms of superconductivity. However, the generation of antivortices, characterized by magnetization antiparallel to the external magnetic field, remains less understood. In this study, we investigate Sn-Pb solder, a superconductor with phase-separated Sn and Pb phases, and report the observation of both vortices and antivortices. Scanning SQUID (superconducting quantum interference device) microscopy revealed the presence of both vortices and antivortices, while magneto-optical imaging demonstrated flux avalanches. Our results demonstrate that Sn in Sn-Pb solder behaves as a type-II superconductor when magnetic fluxes are trapped, despite bulk Sn being a type-I superconductor with a transition temperature (TcSn) of 3.7 K. Our findings suggest that the size effect and proximity effect with Pb contribute synergistically to induce type-II superconductivity in Sn Notably, vortices were observed at temperatures as high as 5 K, exceeding the bulk TcSn. Furthermore, the interplay between the type-I superconducting Pb phase and the type-II superconducting Sn phase results in the generation of antivortices, providing a mechanism to accommodate excess magnetic flux. This study shed light on new research on composites combining type-I and type-II superconductors.
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institution arXiv
publishDate 2025
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spellingShingle Direct Observation of Vortices and Antivortices Generation in Phase-Separated Superconductor Sn-Pb Solder
Arima, Hiroto
Murakami, Takumi
Kinoshita, Yuto
Sepehri-Amin, Hossein
Tokunaga, Masashi
Nojima, Tsutomu
Mizuguchi, Yoshikazu
Superconductivity
Quantized vortices in type-II superconductors provide insights into the mechanisms of superconductivity. However, the generation of antivortices, characterized by magnetization antiparallel to the external magnetic field, remains less understood. In this study, we investigate Sn-Pb solder, a superconductor with phase-separated Sn and Pb phases, and report the observation of both vortices and antivortices. Scanning SQUID (superconducting quantum interference device) microscopy revealed the presence of both vortices and antivortices, while magneto-optical imaging demonstrated flux avalanches. Our results demonstrate that Sn in Sn-Pb solder behaves as a type-II superconductor when magnetic fluxes are trapped, despite bulk Sn being a type-I superconductor with a transition temperature (TcSn) of 3.7 K. Our findings suggest that the size effect and proximity effect with Pb contribute synergistically to induce type-II superconductivity in Sn Notably, vortices were observed at temperatures as high as 5 K, exceeding the bulk TcSn. Furthermore, the interplay between the type-I superconducting Pb phase and the type-II superconducting Sn phase results in the generation of antivortices, providing a mechanism to accommodate excess magnetic flux. This study shed light on new research on composites combining type-I and type-II superconductors.
title Direct Observation of Vortices and Antivortices Generation in Phase-Separated Superconductor Sn-Pb Solder
topic Superconductivity
url https://arxiv.org/abs/2501.17465