Memory effect and triplet pairing generation in the superconducting exchange biased Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 layered heterostructure

Abstract

We fabricated a nanolayered hybrid superconductor-ferromagnet spin-valve structure, the resistive state of which depends on the preceding magnetic field polarity. The effect is based on a strong exchange bias (about -2 kOe) on a diluted ferromagnetic copper-nickel alloy and generation of a long range odd in frequency triplet pairing component. The difference of high and low resistance states at zero magnetic field is 90% of the normal state resistance for a transport current of 250 μA and still around 42% for 10 μA. Both logic states of the structure do not require biasing fields or currents in the idle mode.

Two mechanisms of Josephson phase shift generation by an Abrikosov vortex

“…For example, they can operate as autonomous and persistent phase batteries -one of key elements of quantum [1,[5][6][7][8][9][10][11][12][13][14] and digital Josephson electronics [2,3,15,16]. Such junctions can be also used for development of novel types of cryogenic memory [17][18][19][20][21][22]. The π-phase shift is most commonly needed, e.g., for bringing the flux-qubit to the degeneracy point [1,[5][6][7], for realization of complementary digital Josephson electronics [2,3,15,16] and for maximum distinction between 0 and 1 state in a memory cell [17].…”

Effects of Nb buffer layer on superconducting and magnetic behavior of IrMn/NiFe/Nb/NiFe spin-valves

“…After that, when the sample is saturated in negative fields the alignment is P again [6,9]. In order to estimate some magnetic parameters from the curves, the derivatives of the descending and ascending branches of the loop were calculated [18][19][20] investigated NiFe/IrMn/Co trilayers grown on Ta or Cu seed layers and found that crystalline texture influences the trilayers' magnetic properties [22]. This way, as discussed above, the difference of the H C and H EB values for S Nb when compared to those for S Ta , obtained at 6 K, may be attributed to the degree of (200) preferred orientation of the IrMn layer in S Nb .…”

The effect of normal and insulating layers on 0-πtransitions in Josephson junctions with a ferromagnetic barrier

“…Here g  are the integration constants. In the F layer we can assume small superconducting correlations 1 F q  to linearise the denominator of the left-hand side of (15), which leads us to the equation…”

“…Moreover, a new generation of supercomputers has been developed based on superconducting spintronics [5,6]. One of the main goals of the recent superconducting spintronics development is the creation of rapid single flux quantum logic (RSFQ) elements, such as Josephson phase batteries [7][8][9][10][11][12] and magnetic memory [13][14][15][16][17][18][19][20][21][22][23]. Both, Josephson phase batteries and magnetic memory are based on ferromagnetic Josephson junctions (FJJs).…”