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- All Subjects: Nuclear spin
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Raman spectroscopy characterization of anharmonicity and alloying effects in semiconductor materials
polarization and interface geometry is presented. The 3D model gives the same intrinsic
spin polarization and superconducting gap dependence as the 1D model. This
demonstrates that the 1D model can be use to t 3D data.
Using this model, a Heusler alloy is investigated. Andreev reflection measurements
show that the spin polarization is 80% in samples sputtered on unheated MgO(100)
substrates and annealed at high temperatures. However, the spin polarization is
considerably smaller in samples deposited on heated substrates.
Ferromagnetic FexSix alloys have been proposed as potential spin injectors into
silicon with a substantial spin polarization. Andreev Reflection Spectroscopy (ARS) is
utilized to determine the spin polarization of both amorphous and crystalline Fe65Si35
alloys. The amorphous phase has a significantly higher spin polarization than that of
the crystalline phase.
In this thesis, (1111) Fe SmO0:82F0:18FeAs and Pb superconductors are used to
measure the spin polarization of a highly spin-polarized material, La0:67Sr0:33MnO3.
Both materials yield the same intrinsic spin polarization, therefore, Fe-superconductors
can be used in ARS. Based on the behavior of the differential conductance for highly
spin polarized LSMO and small polarization of Au, it can be concluded that the Fe-Sc
is not a triplet superconductor.
Zero bias anomaly (ZBA), in point contact Andreev reflection (PCAR), has been
utilized as a characteristic feature to reveal many novel physics. Complexities at a
normal metal/superconducting interface often cause nonessential ZBA-like features,
which may be mistaken as ZBA. In this work, it is shown that an extrinsic ZBA,
which is due to the contact resistance, cannot be suppressed by a highly spin-polarized
current while a nonessential ZBA cannot be affected the contact resistance.
Finally, Cu/Cu multilayer GMR structures were fabricated and the GMR% measured
at 300 K and 4.5 K gave responses of 63% and 115% respectively. Not only
do the GMR structures have a large enhancement of resistance, but by applying an
external magnetic eld it is shown that, unlike most materials, the spin polarization
can be tuned to values of 0.386 to 0.415 from H = 0 kOe to H = 15 kOe.
Ultra-short-pulse (USP) lasers in the visible range have been shown to have widespread sterilizing effects on pathogens, which is believed to be caused by mechanical perturbations induced in the pathogen that disrupt essential processes leading to inactivation. This paper demonstrates a complete inactivation of Zika virus, a single-stranded enveloped RNA virus, using USP-laser technology and adds to the growing body of literature on the effectiveness of USP-laser inactivation. The paper also surveys previous inactivation studies to draw inferences about the nature of the Zika virus inactivation. We suggest that the method of inactivation in Zika virus is the selective amalgamation of viral capsid proteins into a nonfunctional mass of proteins because of the laser-induced vibrations, which mechanically prevents the release of viral RNA. The survey of similar inactivation experiments also supports the notion that the viral antigens might be unaffected by USP-laser inactivation, justifying the exploration of vaccine development using USP-laser inactivated Zika virus.