Spin-torque quantization and microwave sensitivity of a nano-sized spin diode

Gleb Demin,Anatoly Popkov,N Perov,A Semisalova

doi:10.1051/epjconf/201818501020

Gleb Demin, Anatoly Popkov + Show 2 more

Open Access

https://doi.org/10.1051/epjconf/201818501020

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Abstract

Rectification of microwave signal by the spin-torque diode is very promising for its practical applications in microwave imaging. This is due to a very high sensitivity of magnetic tunnel junction under the bias current, which was previously demonstrated in a number of works [1-3]. The decreasing of cross-sectional area of the spin-torque diode up to the nano-sized dimensions below 10 nm allows one to reach high sensitivity without any bias current. Transverse quantization of electron states in the magnetic nanowire based on nano-sized metallic spin valves and magnetic tunnel junctions can create an additional impact not only on the magnetoresistance, but also on the spin-transfer torque in such structures. In this work we present an analysis of the quantization effect of conductance and spin-transfer torques on the microwave sensitivity of nano-sized spin-torque diodes during the reduction of its cross-sectional area. It was found that the magnetoresistance values up to 130 % can be achieved in a magnetic nanowire containing spin-valve diode with the nonmagnetic metal spacer. As a result, the maximum microwave sensitivity of spin-torque diodes based on these structures can be increased several times that opens the way for the further development of highly sensitive microwave detectors.

Highlights

Nowadays much attention in the field of spintronics is paid to the consideration of so-called spin-torque diodes based on magnetic tunnel junctions (MTJ), which have a large magnetoresistive effect and demonstrate very high sensitivity to the microwave signal
For that reason there are some problems of the usage of spin-torque diode shifted by bias current
It is of interest to consider an alternative way of increasing the sensitivity of a spin-torque diode. This can be realized by reducing its lateral dimensions, since the spin-torque diode sensitivity increases inversely with the area of MTJ [6]

Summary

Introduction

Nowadays much attention in the field of spintronics is paid to the consideration of so-called spin-torque diodes based on magnetic tunnel junctions (MTJ), which have a large magnetoresistive effect and demonstrate very high sensitivity to the microwave signal. For that reason there are some problems of the usage of spin-torque diode shifted by bias current In this connection, it is of interest to consider an alternative way of increasing the sensitivity of a spin-torque diode. It is of interest to consider an alternative way of increasing the sensitivity of a spin-torque diode This can be realized by reducing its lateral dimensions, since the spin-torque diode sensitivity increases inversely with the area of MTJ [6]. We consider possible effects of quantization of the magnetoresistance and spin-transfer torques in a magnetic nanowire consisting of the metallic spin-valve structure

Charge and spin currents

Quantization of the magnetoresistance and spin-transfer torque

Microwave sensitivity of spin-torque diode based on magnetic nanowire

Findings

Simulation results