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Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Dissertations, Theses, and Masters Projects
This thesis presents optical characterizations of interfaces in ferromagnetic heterostructures and thin films used for spin polarized electronic devices. In these experiments, femtosecond laser spectroscopies are exploited to investigate the interface magnetization reversal, spin precession, and band offset, which are crucial in determining the performances of spintronic devices.;First, magnetization-induced second-harmonic-generation (MSHG) is applied to study interface magnetism in a hybrid structure containing a noncentrosymmetric semiconductor---Fe/AlGaAs. The reversal process of Fe interface layer magnetization is compared with the bulk magnetization reversal. In Fe/AlGaAs (001), the interface magnetization is found to be decoupled from the bulk magnetization based on the different switching …
Studies Of Energy Recovery Linacs At Jefferson Laboratory: 1 Gev Demonstration Of Energy Recovery At Cebaf And Studies Of The Multibunch, Multipass Beam Breakup Instability In The 10 Kw Fel Upgrade Driver, Christopher D. Tennant
Studies Of Energy Recovery Linacs At Jefferson Laboratory: 1 Gev Demonstration Of Energy Recovery At Cebaf And Studies Of The Multibunch, Multipass Beam Breakup Instability In The 10 Kw Fel Upgrade Driver, Christopher D. Tennant
Dissertations, Theses, and Masters Projects
An energy recovering linac (ERL) offers an attractive alternative for generating intense electron beams by approaching the operational efficiency of a storage ring while maintaining the superior beam quality typical of a linear accelerator. Two primary physics challenges exist in pushing the frontier of ERL performance. The first is energy recovering a high energy beam while demonstrating operational control of two coupled beams in a common transport channel. The second is controlling the high average current effects in ERLs, specifically a type of beam instability called multipass beam breakup (BBU). This work addresses each of these issues.;A successful 1 GeV …
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Dissertations, Theses, and Masters Projects
This thesis presents ultrafast laser pump-probe differential transmission experiments on epitaxial CrO2 (110). The experiments were conducted at the wavelengths of 600 nm, 800 nm and 1200 nm, corresponding to the transition energies of 2 eV, 1.5 eV and 1 eV respectively. The wavelength dependent results, comparing with linear optical absorption, revealed the electronic structure of the material. The experimental results also showed polarization dependence of the probe beams. This is attributed to the electronic orbital anisotropy.;Temperature dependence was observed in the pump-probe experiments. The ultrafast transmission data show similar temperature dependence as ultrafast MOKE (Magneto-Optical Kerr Effect) data. A …