Efficient Gating of Magnons by Proximity Superconductors

Abstract

Electrostatic gating confines and controls the transport of electrons in integrated circuits. Magnons, the quanta of spin waves of the magnetic order, are promising alternative information carriers, but difficult to gate. Here we report that superconducting strips on top of thin magnetic films can totally reflect magnons by its diamagnetic response to the magnon stray fields. The induced large frequency shifts unidirectionally blocks the magnons propagating normal to the magnetization. Two superconducting gates parallel to the magnetization create a magnonic cavity. The option to gate coherent magnons adds functionalities to magnonic devices, such as reprogrammable logical devices and increased couplings to other degrees of freedom.

Chirality as Generalized Spin-Orbit Interaction in Spintronics

“…3.2.1 below) [59] in the nonlinear regime and chiral damping by the proximity metallic contact in the linear response (reviewed in Sec. 4.3.2) [241] provides the same phenomenology. Similar mechanism was employed to interpret the experimentally observed non-reciprocity in electrical injection and detection of incoherent magnons of YIG films with thickness 50 nm in Fig.…”

“…One can also use the gating effect to achieve an isolator as shown in Fig. 56(b) that the gate only shifts the dispersion of waves of one direction and thus block the waves from this direction with a total reflection, such as the input 1 , but allows the propagation via input 2 , which also leads to the broadband unidirectional functionality without much complicated design [241,429,430]. This mechanism was proposed in gating the magnon by metal with interfacial DMI [429,430] without chiral interaction and superconductor with chiral interaction [241], but may be generalized in other devices as well in the future.…”

“…• Chiral spin Seebeck effect [50,67] • Additional damping due to spin and magnon pumping [50,51] • Magnon trapping [51] and unidirectional blocking [241] • Magnetic nanowire arrays on thin YIG films [49] • Antiparalle spin valves [54,55] • Two magnetic nanowires on thin YIG films [52] • Enhanced damping and magnon trap [53] Magnons and photons…”

“…We recently [241] found the chiral gating effect of floating superconducting films on top of ultrathin films of a magnetic insulator such as YIG in the configuration of Fig. 39(a).…”

“…3.2.2, can penetrate through the superconductor. It generates the electric field that induces the eddy current in the superconducting layer with components given by [241] ( , ) = 0, (200a) ( ,…”