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Ultrasensitive Measurements of Magnetism in Carbon-based Materials

Scozzaro, Nicolas Joseph
http://rave.ohiolink.edu/etdc/view?acc_num=osu148059474280115

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Physics.
In this dissertation I present MRFM measurements of spin dynamics across the interface between pure a diamond region and a region of densely implanted spins, which we call a `spin wire’. These measurements demonstrate that spin diffusion mediated by spin flip-flops can be the dominant effect that determines the lifetime of spins in nanoscale volumes. In particular, the ability to measure nanoscale volumes illuminates the need to specify exactly what one means by `spin lifetime,’ which most commonly refers to T1, the ensemble spin lattice relaxation time. As the measured ensemble shrinks down to small numbers of spins, or even a single spin, the notion of spin lifetime most intuitively means the amount of time it takes for a spin to flip from up to down. We show that on an individual-spin basis, the spin lifetime can be much less than T1. Although MRFM has reached a number of milestones, one significant capability which has not yet been accomplished is direct measurement of the transverse component of the magnetization. Such a capability would open MRFM to a wealth of techniques commonly used for conventional NMR, which detects the transverse moment inductively. This capability would require matching the nuclear Larmor precession frequency to the mechanical resonance frequency, which is in the MHz regime for typical applied fields. While cantilevers typically have kHz frequencies, there are membrane mechanical resonators that have MHz frequencies. To this end, we began MRFM studies using membranes. In this dissertation I demonstrate the first MRFM measurements of the longitudinal magnetization using a membrane resonator. I show that membranes have a number of advantages compared to cantilevers for MRFM applications, and are a promising candidate for transverse mechanical detection of magnetic resonance. Finally, I use the sensitive technique of cantilever magnetometry to study two-dimensional van der Waals materials. En route to measuring graphene, I measure de Haas van Alphen oscillations from 300 layers of graphite. These measurements demonstrate that cantilever magnetometry is a powerful technique for interrogating the magnetism of 2D materials.
Chris Hammel (Advisor)
Amy Connolly (Committee Member)
Fengyuan Yang (Committee Member)
Mohit Randeria (Committee Member)
162 p.
Physics
Magnetic resonance force microscopy; silicon nitride membranes; diamond; P1 centers; NV centers; powder pattern; graphene; cantilever magnetometry; DPPH; ultrasensitive force detection; ultrasoft cantilevers; spin wire;

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Citations

  • Scozzaro, N. J. (2016). Ultrasensitive Measurements of Magnetism in Carbon-based Materials [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu148059474280115

    APA Style (7th edition)

  • Scozzaro, Nicolas. Ultrasensitive Measurements of Magnetism in Carbon-based Materials. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu148059474280115.

    MLA Style (8th edition)

  • Scozzaro, Nicolas. "Ultrasensitive Measurements of Magnetism in Carbon-based Materials." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu148059474280115

    Chicago Manual of Style (17th edition)

osu148059474280115
212
© 2016, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.