Magnetic anisotropy in ferromagnetic Josephson junctions

TL;DR

This study investigates how magnetic anisotropy affects the behavior of superconductor-insulator-ferromagnet-superconductor Josephson junctions, revealing deviations from standard models due to ferromagnetic layer properties.

Contribution

It introduces a model considering anisotropy and 2D remanent magnetization to explain deviations in magnetic field dependence.

Findings

Critical current behavior varies with ferromagnetic layer thickness and geometry.

Deviations from textbook models are explained by anisotropy effects.

A short Josephson junction model accounts for observed phenomena.

Abstract

Magnetotransport measurements were done on $\Nb/\Al_2\O_3/\Cu/\Ni/\Nb$ superconductor-insulator-ferromagnet-superconductor Josephson tunnel junctions. Depending on ferromagnetic $\Ni$ interlayer thickness and geometry the standard (1d) magnetic field dependence of critical current deviates from the text-book model for Josephson junctions. The results are qualitatively explained by a short Josephson junction model based on anisotropy and 2d remanent magnetization.