Hybrid superconducting heterostructures with magnetic interlayers

Electron transport processes in oxide superconducting heterostructures with epitaxially grown magnetic thin-film interlayers, in which the interaction of superconducting correlations and magnetic ordering occurs due to superconducting and magnetic proximity effects, have been studied experimentally. Hybrid mesa-heterostructures were prepared from thin-film bottom cuprate superconductor (S), magnetic (M) interlayer made of manganite or an antiferromagnetic cuprate, and the upper electrode made from an ordinary superconductor. When the cuprate antiferromagnetic material was replaced by a ferromagnetic manganite interlayer, the superconducting current was suppressed, although the thin magnetic film was several times thinner, 5 nm, and the temperature was lowered to 0.3 K. At low temperatures dependences of differential resistance vs. voltage for mesa-heterostructures with manganite interlayer featured mini-gap low-energy states.

Discrimination of skyrmion chirality via spin–orbit and –transfer torques for logic operation

Recently many works on magnetic memories and logic circuits, which use a magnetic skyrmion have been reported. Previously we micromagnetically simulated a method to switch a chirality of a magnetic skyrmion formed in a magnetic thin film by introducing a pulsed heat spot. In this paper, we propose a method to discriminate the chirality of a skyrmion in a branched nanowire by using spin–orbit torque (SOT) and spin-transfer torque (STT), and confirm the validity of the method by using simulation. The simulated results show that the motion changes depending on the chirality when additional SOT is applied on a skyrmion moving in a branch by STT. This method can be used as a fundamental building block for electrical detection in memory and logic devices using the chirality of skyrmions as a data bit in addition to the presence (and polarity) of the skyrmions as conventionally used, which can be lead to multiple-valued operation.

Control of Dynamics in Weak PMA Magnets

We have recently shown that a hybrid magnetic thin film with orthogonal anisotropies presenting weak stripe domains can achieve a high degree of controllability of its ferromagnetic resonance. This work explores the origin of the reconfigurability through micromagnetic simulations. The static domain structures which control the thin film resonance can be found under a deterministic applied field protocol. In contrast to similar systems reported, our effect can be obtained under low magnetic fields. We have also found through simulations that the spin wave propagation in the hybrid is nonreciprocal: two adjacent regions emit antiparallel spin waves along the stripe domains. Both properties convert the hybrid in a candidate for future magnonic devices at the nanoscale.

Discrimination of Skyrmion Chirality Via Spin-Orbit and -Transfer Torques for Logic Operation

Recently many works on magnetic memories and logic circuits, which use a magnetic skyrmion have been reported. Previously we micromagnetically simulated a method to switch a chirality of a magnetic skyrmion formed in a magnetic thin film by introducing a pulsed heat spot. In this paper, we propose a method to discriminate the chirality of a skyrmion in a branched nanowire by using spin-orbit torque (SOT) and spin-transfer torque (STT), and confirm the validity of the method by using simulation. The simulated results show that the motion changes depending on the chirality when additional SOT is applied on a skyrmion moving in a branch by STT. This method can be used as a fundamental building block for electrical detection in memory and logic devices using the chirality of skyrmions as a data bit in addition to the presence (and polarity) of the skyrmions as conventionally used, which can be lead to multiple-valued operation.