Magnetically controlled chemical potential in field effect devices
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Authors
Ciccarelli, Chiara
Date
2012-10-09Awarding Institution
University of Cambridge
Author Affiliation
Department of Physics
Qualification
Doctor of Philosophy (PhD)
Type
Thesis
Metadata
Show full item recordCitation
Ciccarelli, C. (2012). Magnetically controlled chemical potential in field effect devices (Doctoral thesis). https://doi.org/10.17863/CAM.11721
Description
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Abstract
In this thesis I describe a sensitive technique for quantifying the chemical potential anisotropy of magnetically ordered and spin-orbit coupled materials. An aluminium single electron transistor (SET) lithographically fabricated on top of a magnetic gate is used to characterise the chemical potential anisotropy of Ga0 .97Mno. 03As and Gao.941\1no.o6As. The conductance variation of the SET provides a direct probe of the magnetisation-dependent change in the chemical potential of the magnetic gate with ?eV resolution. The control of the SET conductance by the magnetisation direction of the gate opens the way to a new recording mechanism. Achieving the same control in a semiconductor device represents a first step towards possible applications in computer memories. In the second part of my work I present the measurements on a CoPt gated metal-oxide-semiconductor� field effect transistor. In the last part of my thesis, I present a study of the response of a metal SET to a radio-frequency perturbation, which showed the conditions of maximum sensitivity and set a lower limit to the detection bandwidth of the SET. This study is important for assessing the performance of a prototypical device for detecting fast magnetisation switching or for quantifying the chemical potential anisotropy of magnetic nano-structures that cannot be electrically connected to an electrode, but that are still expected to have interesting anisotropic properties