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Full-Text Articles in Physics
Magnetic Transitions And Scaling In Anisotropic Rare-Earth Glasses, Kevin M. Lee, Michael J. O'Shea, David J. Sellmyer
Magnetic Transitions And Scaling In Anisotropic Rare-Earth Glasses, Kevin M. Lee, Michael J. O'Shea, David J. Sellmyer
David Sellmyer Publications
We report studies of the magnetic critical behavior as a function of anisotropy strength in rare-earth-rich glasses. Anisotropy is induced in Gd-Co by alloying with Tb. The system studied is Gd65-xTbxCo35 and the random magnetic anisotropy (RMA) strength may be increased by increasing x. The x=0 alloy of this series has been shown to exhibit standard critical behavior expected for a second-order phase transition. With increasing x we find deviations from this behavior due to the presence of RMA. We present detailed results for the alloy with composition x=50 at. % and …
Magnetic Properties Of Fe/Nd Multilayer Films, David J. Sellmyer, Z.R. Zhao, Z.S. Shan, S. Nafis
Magnetic Properties Of Fe/Nd Multilayer Films, David J. Sellmyer, Z.R. Zhao, Z.S. Shan, S. Nafis
David Sellmyer Publications
Measurements are reported on the relationship between magnetic properties and microstructure in thin amorphous and crystalline Fe/Nd multilayer films. The samples, denoted by (XÅFe/YÅNd) ( X/Y), were prepared in a multiple-gun sputtering chamber with a microprocessor-controlled rotating table. For X and Y values less than about 20 Å an amorphous compositionally modulated structure is obtained, with magnetic properties characterized by speromagnetic ordering associated with strong Nd random anisotropy. The net magnetization in general lies in the plane of the film. The temperature and composition dependence of the coercivity, magnetization, and transition temperatures are …
Magnetism And Microstructure Of Compositionally Modulated Disordered Fe/Ta Films, Z.S. Shan, Z.R. Zhao, J.G. Zhao, David J. Sellmyer
Magnetism And Microstructure Of Compositionally Modulated Disordered Fe/Ta Films, Z.S. Shan, Z.R. Zhao, J.G. Zhao, David J. Sellmyer
David Sellmyer Publications
Results are presented on compositionally modulated disordered magnetic films of the form (XÅFe/YÅTa), as a function of the modulation wavelength λ≡X+Y. Magnetization, ac susceptibility, torque magnetometry, x-ray diffraction, and Mössbauer measurements are used to probe magnetic transitions and microstructure. For X and Y values less than about 12 Å the structure is amorphous within the layers and compositionally modulated in the direction perpendicular to the film. Films with ultrathin individual layers (1–3 atomic diameters) exhibit perpendicular anisotropy while the thicker ones have in-plane magnetization. Spin-glass and ferromagnetic transitions are observed and are …
Electronic Structure, Photoemission, And Magnetism In Gd2Co And Er2Co Glasses, Sitaram Jaswal, David J. Sellmyer, M. Engelhardt, Z. Zhao, A.J. Arko, K. Xie
Electronic Structure, Photoemission, And Magnetism In Gd2Co And Er2Co Glasses, Sitaram Jaswal, David J. Sellmyer, M. Engelhardt, Z. Zhao, A.J. Arko, K. Xie
David Sellmyer Publications
The electronic and magnetic structures of amorphous Gd2Co and Er2Co are studied by ultraviolet and x-ray photoemission measurements and band calculations. The spectra for both glasses show a band of Co 3d levels centered at a binding energy EB of about -1.0 eV and peaks arising from 4f levels at EB=-8.4 eV and EBapeq2-5–9 eV for Gd and Er, respectively. Magnetization data have shown that a-Gd2Co possesses a ferrimagnetic structure with a small Co moment. The linear-muffin-tin-orbital method is used to perform self-consistent, spin-polarized calculations in …