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PhD Preliminary Oral Exam – Khalid Masood

Determination of Magneto-elastic Constants in Magnetic Thin Film From FMR Spectra

Ferromagnetic resonance (FMR) phenomenon is widely used for characterizing magnetic materials, because of its well established theory to describe the magnetization dynamics. Not surprisingly, FMR spectroscopy was used extensively to determine material properties of magnetic materials, e.g. anisotropy constants, Lande g factor, damping parameter for spin wave propagation, and first and second order magneto-elastic constants for magneto-elastic materials. For magneto-elastic materials, the magnetic anisotropy can be changed under the influence of mechanical strain (Villari effect) and vice versa (Joule effect). Magneto-elastic constants can be evaluated from the change in FMR frequency due to an applied strain. To utilize magneto-elastic materials in different application (e.g. for magnetic recording, spin-wave pumping), a knowledge about the magneto-elastic constants is important. Some application like spin wave pumping, needs the information for damping para! meter as well. In this work, we propose a technique to determine the magneto-elastic constants through angle-resolved and strain induced FMR spectroscopy. In our current setup, the angle between the sample easy axis and the applied magnetic field can be varied arbitrarily to illustrate anisotropic effect of the magnetic samples. These measurements under the influence of strain are beneficial for the precise determination of anisotropic constants. The experimental results will be fitted with the traditional Smit-Beljers equation using a self-consistent fitting algorithm to extract the necessary parameters. The damping parameters can be extracted from the linewidth of the FMR absorption spectra.

Major Advisor: Albrecht Jander
Committee: Pallavi Dhagat
Committee: Raviv Raich
Committee: David Cann
GCR: Henri Jansen

Thursday, June 13, 2019 at 10:00am to 12:00pm

Kelley Engineering Center, 1005
110 SW Park Terrace, Corvallis, OR 97331

Event Type

Lecture or Presentation

Event Topic

Research

Organization
Electrical Engineering and Computer Science
Contact Name

Calvin Hughes

Contact Email

calvin.hughes@oregonstate.edu

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