Temporal evolution of electric transport properties of YBCO Josephson junctions produced by focused Helium ion beam irradiation

Fuente: arXiv
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Autores principales: Karrer, M., Wurster, K., Linek, J., Meichsner, M., Kleiner, R., Goldobin, E., Koelle, D.
Formato: Preprint
Publicado: 2023
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author Karrer, M.
Wurster, K.
Linek, J.
Meichsner, M.
Kleiner, R.
Goldobin, E.
Koelle, D.
author_facet Karrer, M.
Wurster, K.
Linek, J.
Meichsner, M.
Kleiner, R.
Goldobin, E.
Koelle, D.
contents Using a $30\,\mathrm{keV}$ focused He ion beam (He-FIB) with a wide range of irradiation doses $D=100$ to $1000\,\mathrm{ions/nm}$ we fabricated Josephson and resistive barriers within microbridges of epitaxially grown single crystalline YBCO thin films and investigated the change of their electric transport properties with time. One set of samples (#1A) was simply stored at room temperature under nitrogen atmosphere. A second set (#2D) was post-annealed at $90^\circ\,\mathrm{C}$ using high oxygen pressures and a third set (#2E) at low oxygen pressures. We found that for #1A the critical current density $j_c$ at $4.2\,\mathrm{K}$ changes as $j_c\propto\exp(-\sqrt{t/τ})$ with time $t$, where the relaxation times $τ$ increases exponentially with $D$, which can be described within a limited diffusion based model. In order to increase the diffusion rate we annealed the junctions from #2D at $90^\circ\,\mathrm{C}$ for $30\,\mathrm{min}$ in oxygen environment. Directly after annealing the critical current density $j_c$ increased, while the normal state resistance $R_n$ decreased. Repeated measurements showed that within a week the junctions relaxed to a quasi-stable state, in which the time scale for junction parameter variations increased to several weeks, making this a feasible option to achieve temporal stability of parameters of He-FIB Josephson junctions in YBCO.
format Preprint
id arxiv_https___arxiv_org_abs_2304_02749
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Temporal evolution of electric transport properties of YBCO Josephson junctions produced by focused Helium ion beam irradiation
Karrer, M.
Wurster, K.
Linek, J.
Meichsner, M.
Kleiner, R.
Goldobin, E.
Koelle, D.
Superconductivity
Using a $30\,\mathrm{keV}$ focused He ion beam (He-FIB) with a wide range of irradiation doses $D=100$ to $1000\,\mathrm{ions/nm}$ we fabricated Josephson and resistive barriers within microbridges of epitaxially grown single crystalline YBCO thin films and investigated the change of their electric transport properties with time. One set of samples (#1A) was simply stored at room temperature under nitrogen atmosphere. A second set (#2D) was post-annealed at $90^\circ\,\mathrm{C}$ using high oxygen pressures and a third set (#2E) at low oxygen pressures. We found that for #1A the critical current density $j_c$ at $4.2\,\mathrm{K}$ changes as $j_c\propto\exp(-\sqrt{t/τ})$ with time $t$, where the relaxation times $τ$ increases exponentially with $D$, which can be described within a limited diffusion based model. In order to increase the diffusion rate we annealed the junctions from #2D at $90^\circ\,\mathrm{C}$ for $30\,\mathrm{min}$ in oxygen environment. Directly after annealing the critical current density $j_c$ increased, while the normal state resistance $R_n$ decreased. Repeated measurements showed that within a week the junctions relaxed to a quasi-stable state, in which the time scale for junction parameter variations increased to several weeks, making this a feasible option to achieve temporal stability of parameters of He-FIB Josephson junctions in YBCO.
title Temporal evolution of electric transport properties of YBCO Josephson junctions produced by focused Helium ion beam irradiation
topic Superconductivity
url https://arxiv.org/abs/2304.02749