Fabrication and characterization of ferromagnetic tips for magnetic resonance force microscopy

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dc.contributor.advisor Hammel, Peter C.
dc.contributor.advisor Clymer, Bradley D.
dc.creator Steward, Ross A.
dc.date.accessioned 2010-02-05T16:30:43Z
dc.date.available 2010-02-05T16:30:43Z
dc.date.issued 2008-06
dc.identifier.uri http://hdl.handle.net/1811/44747
dc.description.abstract This thesis deals with the custom fabrication of micron scale rare-earth ferromagnetic tips for use in magnetic resonance force microscopy (MRFM) experiments. Magnetic resonance force microscopy is a three dimensional subsurface imaging technique with the potential for atomic scale sensitivity and resolution. Tips are fabricated here by gluing particles as small as 1 μm to end of atomic force microscopy (AFM) cantilevers and milling the particles to a desired size and shape by sputtering material off using a focused beam of gallium ions. Particle gluing followed by focused ion beam (FIB) milling is shown here to be a promising and, so far, somewhat effective technique for fabricating optimal ferromagnetic tips for certain MRFM experiments. Fabrication results displaying ferromagnetic tips possessing sharp points with radii smaller than 50 nm are presented here. One of the major problems that has been encountered when FIB milling small particles is a loss in coercivity, sometimes from around 10,000 Gauss to less than 100 Gauss. Although indications lead to the conclusion that ion beam related damage is the cause of this decrease in coercivity, this assertion has not yet been proven. Based on the results of simulations and previous research it is believed that the loss of coercivity is related to particle heating caused by ion beam exposure, rather than direct damage caused by impinging ions from the beam or secondary recoil atoms knocked loose by the beam. This loss in coercivity is one of several different sources of variability that leads to inconsistent fabrication results. Room temperature cantilever magnetometry is shown here to be an extremely sensitive, time efficient, and economical technique for determining certain magnetic properties of the tip including magnetic moment, hysteresis loop, and anisotropy. Results are presented here from measurements on magnetic tips micron scale dimensions and moments as small as 10^(-13) J/T. Calculations described here show the theoretical sensitivity limit of the room temperature magnetometer to be as high as 4 x 10^(-17) J/T using commercially available AFM cantilevers. en_US
dc.description.sponsorship Hammel Startup Fund en_US
dc.language.iso en_US en_US
dc.publisher The Ohio State University en_US
dc.relation.ispartofseries The Ohio State University. Department of Electrical and Computer Engineering Honors Theses; 2008 en_US
dc.subject magnetometer en_US
dc.subject magnetometry en_US
dc.subject focused ion beam en_US
dc.subject cantilever en_US
dc.subject interferometer en_US
dc.subject interferometry en_US
dc.title Fabrication and characterization of ferromagnetic tips for magnetic resonance force microscopy en_US
dc.type Thesis en_US
dc.description.embargo A one-year embargo was granted for this item. en_US
dc.rights.cc Attribution-ShareAlike 3.0 Unported en_US
dc.rights.ccuri http://creativecommons.org/licenses/by-sa/3.0/ en_US
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