Spin Transfer Torque in Antiferromagnetic Spin-Valves: From Clean to Disordered Regimes

Current-driven spin torques in metallic spin-valves composed of antiferromagnets are theoretically studied using the non-equilibrium Green's function method implemented on a tight-binding model. We focus our attention on G-type and L-type antiferromagnets in both clean and disordered regimes. In such structures, spin torques can either rotate the magnetic order parameter coherently (coherent torque) or compete with the internal antiferromagnetic exchange (exchange torque). We show that, depending on the symmetry of the spin-valve, the coherent and exchange torques can be either in the plane, {\alpha} n\times(q \times n) or out of the plane {\alpha} n \times q, where q and n are the directions of the order parameter of the polarizer and the free antiferromagnetic layers, respectively. Although disorder conserves the symmetry of the torques, it strongly reduces the torque magnitude, pointing out the need for momentum conservation to ensure strong spin torque in antiferromagnetic spin-valvesComment: 10 pages, 11 figure

From Bulk to Nano

With the emergence of countless applications particularly on a nanoscale, and their unpredictable implications mostly on a macroscale, it may seem that different aspects of magnetism are unrelated. This book addresses the relationship between apparently unconnected topics in magnetism

Magnetism: Basics and Applications /

This textbook is aimed at engineering students who are likely to come across magnetics applications in their professional practice. Whether designing lithography equipment containing ferromagnetic brushes, or detecting defects in aeronautics, some basic knowledge of 21st century magnetism is needed. From the magnetic tape on the pocket credit card to the read head in a personal computer, people run into magnetism in many products. Furthermore, in a variety of disciplines tools of the trade exploit magnetic principles, and many interdisciplinary laboratory research areas cross paths with magnetic phenomena that may seem mysterious to the untrained mind. Therefore, this course offers a broad coverage of magnetism topics encountered more often in this millenium, revealing key concepts on which many practical applications rest. Some traditional subjects in magnetism are discussed in the first half of the book, followed by areas likely to spark the curiosity of those more interested in today’s technological achievements. Although sometimes some aspects may seem difficult to comprehend at first, bibliography directs the reader to appropriate further study. Throughout the chapters, the student is encouraged to discover the not-so-obvious associations between different magnetics topics, a task that will prove to be at the very least rewarding