Table of Contents
Table of Contents
Chapter 1. Introduction
Chapter 2. Formulation and the Method
Chapter 3. Ferromagnetic Spintronics
Chapter 4. Antiferromagnetic Spintronics
Chapter 5. Ferromagnetic Quantum Coherence
Chapter 6. Antiferromagnetic Quantum Coherence
Chapter 7. Summary and Discussion
“Spintronics” is the field wherein the net spin of an ensemble of electrons is non-zero. One can monitor the degree of spin polarization in order to study the source of the spin polarization and/or use the polarized electrons to control the behavior of another system. The degree of polarization can be controlled by varying the electric current passing through a layer of metal whose electrons are spin polarized.
This monograph deals with the use of spin polarized electrons to affect the behavior of a magnetic layer, either ferromagnetic or antiferromagnetic. The magnetic layer is macroscopic in that it contains many electrons, perhaps as many as one hundred thousand, yet small enough as to be able to exhibit the phenomenon of “macroscopic quantum tunneling” – referred to as “MQT”. MQT is a phenomenon that occurs at the crossover between the quantum level and the microscopic level and has been richly studied for the past few decades in a number of systems. To observe MQT of magnetization, the magnetization is oriented, typically by an external magnetic field, so that its energy is in a potential well with a barrier of extremely small height so that the magnetization can spontaneously make a transition into a neighboring well at a reasonably large rate.
The transition rate is affected by dissipation. For an isolated sample of a magnetic layer, the dissipation is fixed. However, since spin polarization contributes to the dissipation, our ability to control the degree of spin polarization allows us to control the degree of dissipation in the magnetic layer. That control is an extremely useful tool in a study of the effect of dissipation on MQT.
The ultimate goal of this monograph is to provide the reader with the transition rates of a ferromagnetic or antiferromagnetic layer that has various crystalline structures. The author has been a leader in the field of making these complex calculations so that the results should be of great use to researchers in this field.
The reader should certainly have studied quantum theory at an advanced level. To follow the calculations, the reader should have a background in the use of path integrals to calculate transitions rates for MQT.” – Leon Gunther, Emeritus Professor of Physics, Tufts University
Researchers and Graduate students in Physics, Materials science and Materials Engineering, in general, and especially those working in the problem of macroscopic quantum phenomena. People such as those working with spintronics, memory storage, etc., should find the book useful especially in regards to the idea of reducing power loss, and increasing efficiency in systems of spintronics.
Quantum Physics, macroscopic quantum coherence, metastable states, quantum and classical transitions, magnetization and Ne’el vector transitions, dissipative systems, ferromagnetic and antiferromagnetic spintronics