Analisis Bifurkasi Fluxon pada Persambungan Josephson Bertipe Superkonduktor-Feromagnetik-Superkonduktor (S/F/S)

Abstract

Dynamics for the Josephson junction of type S/F/S is different from ordinary Josephon junction, where on the junction is contained the addition of tribal sin 2φ which is the result of the second harmonic supercurrent on the Josephson junction of type S/F/S that is related to Shapiro Steps symptoms. Research has been done is analyze the fluxon bifurcation to determine the stability of the fluxon in a Josephson junction of type S/F/S. The analysis was done by using the approach of analytically dynamics system and assisted by numerical solution that uses the application ODE 45 on MATLAB. The result of the critical point and the bifurcation types which is obtained to show the normalized damping (β and ϳₑ) does not affect the change of fluxon stability at the limit of less than one. Parameter β only affects the type of critical point and bifurcation that occurs, if β = 0, for ϳₑ = 0 and ϳₑ = 0.4 the bifurcation occurs is a saddle-center, and if β = 0.5 the bifurcation is a saddle-focus. Parameter ϳₑ affects the amplitude on the generated fluxon oscillation, if ϳₑ = 0 the fluxon amplitude is very small, whereas if ϳₑ = 0.4 the amplitude is larger. In each case, the fluxon stability is affected by the first harmonic supercurrents which is different sign, those are when ϳ₁ < 0 the fluxon is always stable, whereas when ϳ₁ < 0 fluxon is unstable at first but it tends towards to the point of its stability.