Electric Effects in Paramagnetic Resonance

Abstract

FINESSE is a software simulation allowing one to compute the optical properties of laser interferometers used by interferometric gravitational-wave detectors today. This fast and versatile tool has already proven to be useful in the design and commissioning of gravitational-wave detectors. The basic algorithm of FINESSE numerically computes the light amplitudes inside an interferometer using Hermite-Gauss modes in the frequency domain. In addition, FINESSE provides a number of commands for easily generating and plotting the most common signals including power enhancement, error and control signals, transfer functions and shot-noise-limited sensitivities. Among the various simulation tools available to the gravitational wave community today, FINESSE provides an advanced and versatile optical simulation based on a general analysis of user-defined optical setups and is quick to install and easy to use. PACS numbers: 04.80. Nn, 95.55.Ym, 07.60.Ly, 42.25.Hz

Electrically active magnetic excitations in antiferromagnets (Review Article)

“…Obviously, the dynamical interplay between magnetic and electric excitations has been reasonably expected for these materials, as well. Indeed, soon after the work [14], the observation of electric-dipole active magnetic excitations were reported for TbMnO 3 and GdMnO 3 as far-infrared absorption near 2.5 meV [9,10].…”

“…Such perovskite manganites as TbMnO 3 and GdMnO 3 are examles of typical family members of multiferroics with a ferroelectricity induced by magnetic order. Exactly for these compounds, apparently for the first time, the strong experimental evidence was obtained of new type of magnetic excitations, namely the electric-dipole active magnons or electromagnons [9,10].…”

“…In this way a possibility to excite transitions forbidden for a conventional magnetic resonance was demonstrated. In further investigations, electrically induced transitions between spin levels were detected for different magnetic ions and explored in a number of reports (see review [3] and textbooks [4,5]). …”

“…From viewpoint of theory, there are no principal differences between the static and alternating field; it is only important that related magnetoelectric constants, R ijk and T ijk , must be nonzero as well as the corresponding matrix elements. Let us remind that linear electric effects are feasible (the magnetoelectric constants are nonzero) for paramagnetic ions in the non-center-symmetric positions [3][4][5]. Obviously, in concentrated magnetic compounds the existence of ions with electric-dipole active magnetic transitions yields collective magnetic excitations.…”

“…It should be noted that the possibility to induce the magnetic resonance transitions by an alternating electric field follows already from the spin Hamiltonian of the form H = E i (R ijk S j S k + T ijk H j S k ); i, j, k = x, y, z, which is used for description of linear electric field effects (here S is the spin operator, H stands for external magnetic field) [3][4][5]. From viewpoint of theory, there are no principal differences between the static and alternating field; it is only important that related magnetoelectric constants, R ijk and T ijk , must be nonzero as well as the corresponding matrix elements.…”