17-03-2014, 03:20 PM
Metal-based spintronic devices
INTRODUCTION
The simplest method of generating a spin-polarised current in a metal is to pass the current through a ferromagnetic material. The most common application of this effect is a giant magnetoresistance (GMR) device. A typical GMR device consists of at least two layers of ferromagnetic materials separated by a spacer layer. When the two magnetization vectors of the ferromagnetic layers are aligned, the electrical resistance will be lower (so a higher current flows at constant voltage) than if the ferromagnetic layers are anti-aligned. This constitutes a magnetic field sensor.
Two variants of GMR have been applied in devices: (1) current-in-plane (CIP), where the electric current flows parallel to the layers and (2) current-perpendicular-to-plane (CPP), where the electric current flows in a direction perpendicular to the layers.
Other metals-based spintronics devices:
Tunnel magnetoresistance (TMR), where CPP transport is achieved by using quantum-mechanical tunneling of electrons through a thin insulator separating ferromagnetic layers.
Spin-transfer torque, where a current of spin-polarized electrons is used to control the magnetization direction of ferromagnetic electrodes in the device.
Spin-wave logic devices utilize the phase to carry information. Interference and spin-wave scattering are utilized to perform logic operations.
Spintronic-logic devices
Non-volatile spin-logic devices to enable scaling beyond the year 2025[11] are being extensively studied. Spin-transfer torque-based logic devices that use spins and magnets for information processing have been proposed[12] and are being extensively studied at Intel.[13] These devices are now part of the ITRS exploratory road map and have potential for inclusion in future computers. Logic-in memory applications are already in the development stage at Crocus[14] and NEC.[15]
INTRODUCTION
The simplest method of generating a spin-polarised current in a metal is to pass the current through a ferromagnetic material. The most common application of this effect is a giant magnetoresistance (GMR) device. A typical GMR device consists of at least two layers of ferromagnetic materials separated by a spacer layer. When the two magnetization vectors of the ferromagnetic layers are aligned, the electrical resistance will be lower (so a higher current flows at constant voltage) than if the ferromagnetic layers are anti-aligned. This constitutes a magnetic field sensor.
Two variants of GMR have been applied in devices: (1) current-in-plane (CIP), where the electric current flows parallel to the layers and (2) current-perpendicular-to-plane (CPP), where the electric current flows in a direction perpendicular to the layers.
Other metals-based spintronics devices:
Tunnel magnetoresistance (TMR), where CPP transport is achieved by using quantum-mechanical tunneling of electrons through a thin insulator separating ferromagnetic layers.
Spin-transfer torque, where a current of spin-polarized electrons is used to control the magnetization direction of ferromagnetic electrodes in the device.
Spin-wave logic devices utilize the phase to carry information. Interference and spin-wave scattering are utilized to perform logic operations.
Spintronic-logic devices
Non-volatile spin-logic devices to enable scaling beyond the year 2025[11] are being extensively studied. Spin-transfer torque-based logic devices that use spins and magnets for information processing have been proposed[12] and are being extensively studied at Intel.[13] These devices are now part of the ITRS exploratory road map and have potential for inclusion in future computers. Logic-in memory applications are already in the development stage at Crocus[14] and NEC.[15]