Novel microwave oscillator driven by spinning current

Abstract

Disclosed is a spin-polarized current-driven microwave oscillator structure and a preparation method thereof, belonging to the field of spin transportation device technology, which is characterized in that an oxidized silicon substrate is adopted to prepare a multi-layer structure through the ultra-high vacuum magnetron sputtering, and then the multi-layer structure is processed into a columnar structure which has a horizontal size of 100+-50 nm through electron beam lithography, Ar ion beam etching, positive photoresist stripping and other microelectronics technologies. An upper electrode and a lower electrode are produced on the top layer of the multi-layer membrane structure and on the surface of the bottom-layer membrane, and the current injection direction is perpendicular to the plane of the metal multi-layer membrane. The invention has advantages that the initial magnetization directions of the fixed layer and the free layer are both located within the membrane plane and are perpendicular to each other, so that the free layer obtains the largest horizontal spin injection, so as to achieve substantial spin precession, to facilitate the obtaining of large microwave power output without any requirements of adding external magnetic field.

Description

technical field [0001] The invention belongs to the field of spin transport devices, in particular to the structure and preparation method of a novel microwave device based on the spin transfer effect. The device can be used in microwave communication and phase-locking technology and other fields. Background technique [0002] In recent years, spintronics has become a hot field of condensed matter physics due to its rich physical connotation and broad device application prospects. In 1996, scientists theoretically predicted a new spin-related effect at the nanoscale—the spin transfer effect, which injected new vitality into this field. Through the spin transfer torque between the injected spin-polarized current and the local electrons in the ferromagnetic layer, the magnetic moment of the ferromagnetic layer can be changed periodically, resulting in the magnetoresistance of the device changing with time. Change, generate alternating voltage, and obtain microwave power outp...

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Problems solved by technology

The modulation range of the microwave oscillator based on the spin transfer effect reported in the literature can reach 1~200GHz, and the quality factor can reach more than 4000 [PRIBIAG V S, et al. "Magnetic vortex oscillator driven by d.c.spin-polarized current". NaturePhysics, 2007, 3(7): 498-503.], but before the practical application, there are still some key issues to be resolved

First of all, the power of microwave transmission is low, only on the order of nanowatts, which cannot meet the practical requirements; secondly, the efficiency of microwave emission is too low, requiring a large injection current and external magnetic field

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