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Time and Space Resolved Spin-Heat Transport in the Magnetic Insulator Yttrium Iron Garnet

Jamison, John S
http://rave.ohiolink.edu/etdc/view?acc_num=osu1586740671277489

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Materials Science and Engineering.
The intrinsic spin Seebeck effect (SSE) describes the thermally driven spin currents within the bulk of materials. The intrinsic SSE current in yttrium iron garnet (YIG) drives a secondary bulk spin current at material boundaries and interfaces. The nonequilibrium magnons which carry this second spin current are parameterized by the magnon chemical potential, with a diffusion length of several microns in YIG. High speed transient optothermal measurements of SSE are performed on a platinum/yttrium iron garnet bilayer across a broad range of temperatures from 4 to 300 K. Interfacial SSE, driven by an electron magnon temperature difference develops over short time scales, ns, while the magnon chemical potential driven by intrinsic SSE develops over hundreds of microseconds. Time dependent SSE data are fit to a multi-temperature coupled spin-heat transport model using the finite element method (FEM). The nonequilibrium magnon lifetime, magnon-phonon thermalization time and an interfacial to intrinsic scaling ratio are used as free parameters to fit the data. The lifetime varies from 2 to 60 microseconds, and the low temperature drop is consistent with the relaxation of low energy magnons by impurities reported in ferromagnetic resonance measurements. The magnon-phonon thermalization time varies from 100 picoseconds to 20 nanoseconds. A nonmonotonic time dependence of SSE at low temperature is explained by the nonequilibrium between magnon and phonon temperatures, controlled by the thermalization time.
Roberto Myers (Advisor)
Joseph Heremans (Committee Member)
Fengyuan Yang (Committee Member)
162 p.
Condensed Matter Physics; Energy; Materials Science; Solid State Physics
magnons; spin caloritronics; yttrium iron garnet; spin seebeck; magnon phonon interaction; magnonics; spin thermal;

Recommended Citations

Citations

  • Jamison, J. S. (2020). Time and Space Resolved Spin-Heat Transport in the Magnetic Insulator Yttrium Iron Garnet [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586740671277489

    APA Style (7th edition)

  • Jamison, John. Time and Space Resolved Spin-Heat Transport in the Magnetic Insulator Yttrium Iron Garnet. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1586740671277489.

    MLA Style (8th edition)

  • Jamison, John. "Time and Space Resolved Spin-Heat Transport in the Magnetic Insulator Yttrium Iron Garnet." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586740671277489

    Chicago Manual of Style (17th edition)

osu1586740671277489
411
© 2020, some rights reserved.Creative Commons License Time and Space Resolved Spin-Heat Transport in the Magnetic Insulator Yttrium Iron Garnet by John S Jamison is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.