Nanoscale Semiconductor Memories

9	Magnetic Domain Wall “Racetrack” Memory Michael C. Gaidis and Luc Thomas

CONTENTS

9.1    Elements of Racetrack Memory

9.1.1    General Description of Racetrack Memory

9.1.2    Domain Wall Storage in a Nanowire

9.1.2.1    Material Considerations: Perpendicular versus In-Plane Magnetic Anisotropies

9.1.2.2    Domain Wall Structure and Width

9.1.2.3    Scaling and Storage Density Considerations

9.1.3    Domain Wall Writing

9.1.4    Readout

9.1.4.1    Methods of Electrical Domain Wall Detection

9.1.4.2    Readout with a Magnetic Tunnel Junction

9.1.5    Domain Wall Shifting

9.1.5.1    Spin-Polarized Current and Spin-Transfer Torque

9.1.5.2    Adiabatic and Nonadiabatic Spin Transfer Torques

9.1.5.3    Critical Current Density for Depinning: ...