Nonlocal feedback in ferromagnetic resonance

Ferromagnetic resonance in thin films is analyzed under the influence of spatiotemporal feedback effects. The equation of motion for the magnetization dynamics is nonlocal in both space and time and includes isotropic, anisotropic and dipolar energy contributions as well as the conserved Gilbert- and the non-conserved Bloch-damping. We derive an analytical expression for the peak-to-peak linewidth. It consists of four separate parts originated by Gilbert damping, Bloch-damping, a mixed Gilbert-Bloch component and a contribution arising from retardation. In an intermediate frequency regime the results are comparable with the commonly used Landau-Lifshitz-Gilbert theory combined with two-magnon processes. Retardation effects together with Gilbert damping lead to a linewidth the frequency dependence of which becomes strongly nonlinear. The relevance and the applicability of our approach to ferromagnetic resonance experiments is discussed.Comment: 22 pages, 9 figure

Gilbert damping and spin Coulomb drag in a magnetized electron liquid with spin-orbit interaction

We present a microscopic calculation of the Gilbert damping constant for the magnetization of a two-dimensional spin-polarized electron liquid in the presence of intrinsic spin-orbit interaction. First we show that the Gilbert constant can be expressed in terms of the auto-correlation function of the spin-orbit induced torque. Then we specialize to the case of the Rashba spin-orbit interaction and we show that the Gilbert constant in this model is related to the spin-channel conductivity. This allows us to study the Gilbert damping constant in different physical regimes, characterized by different orderings of the relevant energy scales -- spin-orbit coupling, Zeeman coupling, momentum relaxation rate, spin-momentum relaxation rate, spin precession frequency -- and to discuss its behavior in various limits. Particular attention is paid to electron-electron interaction effects,which enter the spin conductivity and hence the Gilbert damping constant via the spin Coulomb drag coefficient.Comment: 18 pages, 8 figure

Finding the Best QoS Path in a Gilbert Channel Network

Many different types of modern wired and wireless communication links can be mathematically described as discrete- time Gilbert channels. In this extended abstract, we present an exact method of calculating the best path in a network of discrete- time Gilbert channels, each of which is defined as a Markov chain with two states. In the "Good" state of the chain, the channel produces no erasure, and in the "Bad" state of the chain, the channel produces an erasure. Our method relies on a modified version of the Dijkstra's algorithm, which we customize to operate on sets of Gilbert channel parameters, instead of real numbers. We prove that the Gilbert channels obeys a certain set of algebraic properties which makes it compatible with our algorithm

Enhancement of the Gilbert damping constant due to spin pumping in noncollinear ferromagnet/nonmagnet/ferromagnet trilayer systems

We analyzed the enhancement of the Gilbert damping constant due to spin pumping in non-collinear ferromagnet / non-magnet / ferromagnet trilayer systems. We show that the Gilbert damping constant depends both on the precession angle of the magnetization of the free layer and on the direction of the magntization of the fixed layer. We find the condition to be satisfied to realize strong enhancement of the Gilbert damping constant.Comment: 4 pages, 3 figures, to be published in Phys. Rev.

Charles H. Gilbert, Pioneer Ichthyologist and Fishery Biologist

Charles Henry Gilbert (Fig. 1) was a pioneer ichthyologist and, later, fishery biologist of particular significance to natural history of the western United States. Born in Rockford, Illinois on 5 December 1859, he spent his early years in Indianapolis, Indiana, where, in 1874, he came under the influence of his high school teacher, David Starr Jordan (1851-1931). Gilbert graduated from high school in 1875, and when Jordan became a professor of natural history at Butler University in Irvington, Indiana, Gilbert followed, and received his B.A. degree in 1879. Jordan moved to Indiana University, in Bloomington, in the fall of 1879, and Gilbert again followed, earning his M.S. degree in 1882 and his Ph.D. in 1883 in zoology. His doctorate was the first ever awarded by Indiana University