Voltage Control of Magnetism in THz Regime via Magnon-Phonon Coupling
Abstract
There is currently a high level of interest in using magnetic systems in the THz regime for applications like transduction, electronic filtering, and logic. However there are two main problems prohibiting advancement in this field. The first is a lack of fundamental knowledge concerning magnon/phonon coupling at THz frequencies. The second problem, related to the first, is that traditional ferromagnetic systems have a frequency response limited to the low GHz range. To address both of these problems, we propose to investigate a class of magnetoelastic antiferromagnetic materials that offer THz operations using voltage-induced strains provided by a piezoelectric layer, i.e. phonons to control magnons. Specifically, we intend to fabricate nanoscale magnetoelastic antiferromagnetic elements onto thin piezoelectric films. A dynamic voltage applied to the piezoelectric material produces THz strain oscillations in the antiferromagnetic elements causing magnetic reorientation attributable to magnon/phonon interaction. This new approach provides an energy efficient technique to reorient magnetic states at THz frequencies essential for future applications. In this proposal, we present a three-step plan to understand the dynamic magnetoelastic response of a heterogeneous antiferromagnetic material. The plan consists of 1) fundamental modeling, 2) material development, and 3) testing/evaluation of a strain-mediated voltage- controlled heterogeneous antiferromagnetic material. The proposal relies on an experimental program that is informed by sophisticated modeling rather than following a Òmake-it-and-test-itÓ approach. Developing a new magnetoelastic antiferromagnetic material is outside the scope of this proposal, rather we focus on evaluating the dynamic response of existing materials with known magnetoelastic coupling. One such material is the y-phase AFM alloy Fe50Mn50 producing giant magnetostriction (800 ppm) at room temperature. Finally, the testing phase consists of two components: 1) sophisticated national lab-based testing to evaluate spin states with atomic specificity, and 2) university-based benchtop testing to demonstrate picosecond reorientation. The proposed research represents one of the first investigations into the magnon/phonon coupling behavior at THZ frequencies using antiferromagnetic materials. Understanding the complex dynamics through modeling, fabrication and testing provides a clear path to explore fundamental physics in the context of new and interesting application spaces. Namely, the research proposed here will enable 1) new classes of THz electronic devices and 2) new computational methods verified with experiments, and 3) a fundamental THz magnon/phonon interactions. This work has the potential to provide a major shift towards cheaper and aster electronics devices in future applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 11, 2018
- Source ID
- W911NF1710364
Entities
People
- Gregory P. Carman
Organizations
- Army Contracting Command
- United States Army
- University of California, Los Angeles