In tunnel magnetic Josephson junctions (JJs), we have provided evidence of an inverse magnetic dependence of the critical current I-c(H), i.e., a shift of the I-c(H) curves in the opposite expected direction. We have established a self-consistent method to ascribe this unconventional feature to spin polarization phenomena at the S/F interface. Through a magnetic characterization of Superconductor (S) /Ferromagnet (F) /Superconductor (S) trilayers and a magnetostatic analysis of the devices, we show that the F-stray fields fail to determine the pattern inversion. The comparative analysis with the literature supports our thesis that this phenomenon can be explained in terms of inverse proximity effect and observed with a proper choice of materials and thickness of the ferromagnetic layer involved in the junction structure. More generally, our approach proves that a careful investigation of the magnetic field pattern in magnetic JJs can lead to the detection of novel effects arising at the S/F interface.
Investigation of the Inverse Magnetic Hysteresis of the Josephson Supercurrent in Magnetic Josephson Junctions
Vettoliere Antonio;Granata Carmine;Lamura Gianrico;
2022
Abstract
In tunnel magnetic Josephson junctions (JJs), we have provided evidence of an inverse magnetic dependence of the critical current I-c(H), i.e., a shift of the I-c(H) curves in the opposite expected direction. We have established a self-consistent method to ascribe this unconventional feature to spin polarization phenomena at the S/F interface. Through a magnetic characterization of Superconductor (S) /Ferromagnet (F) /Superconductor (S) trilayers and a magnetostatic analysis of the devices, we show that the F-stray fields fail to determine the pattern inversion. The comparative analysis with the literature supports our thesis that this phenomenon can be explained in terms of inverse proximity effect and observed with a proper choice of materials and thickness of the ferromagnetic layer involved in the junction structure. More generally, our approach proves that a careful investigation of the magnetic field pattern in magnetic JJs can lead to the detection of novel effects arising at the S/F interface.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.