Open Access. Powered by Scholars. Published by Universities.®
Electromagnetics and Photonics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- File Type
Articles 1 - 10 of 10
Full-Text Articles in Electromagnetics and Photonics
Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris
Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris
Laura H. Lewis
Ferromagnetic air-stable SmCo nanoparticles have been produced directly using a one-step chemical synthesis method. X-ray diffraction studies confirmed the formation of hexagonal SmCo5 as a dominant phase. High resolution transmission electron microscopy confirms the presence of uniform, anisotropic bladelike nanoparticles approximately 10 nm in width and 100 nm in length. Values of the intrinsic coercivity and the magnetization in the as-synthesized particles are 6.1 kOe and 40 emu/g at room temperature and 8.5 kOe and 44 emu/g at 10 K, respectively. This direct synthesis process is environmentally friendly and is readily scalable to large volume synthesis to meet the needs …
M-Type Barium Hexaferrite Synthesis And Characterization For Phase Shifter Applications, A. T. Wise, J. Rocks, D. E. Laughlin, M. E. Mchenry, S. D. Yoon, C. Vittoria, V. G. Harris
M-Type Barium Hexaferrite Synthesis And Characterization For Phase Shifter Applications, A. T. Wise, J. Rocks, D. E. Laughlin, M. E. Mchenry, S. D. Yoon, C. Vittoria, V. G. Harris
Vincent G. Harris
M-type barium hexaferrite films have been grown by liquid phase epitaxy and examined by x-ray diffraction, scanning electron microscopy, atomic force microscopy, and conventional and Lorentz-mode transmission electron microscopy (TEM). These films exhibit a diamond chevron shaped "brick wall" microstructure with c-axis oriented hexaferrite platelets. The films are oriented with their c axes in-plane, and parallel to the M-plane sapphire substrate, and exhibit a 30 degrees rotation about the c axis with respect to the substrate. Rocking curves showed (20-20) and (22-40) FWHM values of 1.09 degrees and 1.56 degrees, respectively, for the thinner of two samples, and 0.31 degrees …
M-Type Barium Hexaferrite Synthesis And Characterization For Phase Shifter Applications, A. T. Wise, J. Rocks, D. E. Laughlin, M. E. Mchenry, S. D. Yoon, C. Vittoria, V. G. Harris
M-Type Barium Hexaferrite Synthesis And Characterization For Phase Shifter Applications, A. T. Wise, J. Rocks, D. E. Laughlin, M. E. Mchenry, S. D. Yoon, C. Vittoria, V. G. Harris
Carmine Vittoria
M-type barium hexaferrite films have been grown by liquid phase epitaxy and examined by x-ray diffraction, scanning electron microscopy, atomic force microscopy, and conventional and Lorentz-mode transmission electron microscopy (TEM). These films exhibit a diamond chevron shaped "brick wall" microstructure with c-axis oriented hexaferrite platelets. The films are oriented with their c axes in-plane, and parallel to the M-plane sapphire substrate, and exhibit a 30 degrees rotation about the c axis with respect to the substrate. Rocking curves showed (20-20) and (22-40) FWHM values of 1.09 degrees and 1.56 degrees, respectively, for the thinner of two samples, and 0.31 degrees …
Effect Of Growth Temperature On The Magnetic, Microwave, And Cation Inversion Properties On Nife₂O₄ Thin Films Deposited By Pulsed Laser Ablation Deposition, C. N. Chinnasamy, S. D. Yoon, Aria Yang, Ashish Baraskar, C. Vittoria, V. G. Harris
Effect Of Growth Temperature On The Magnetic, Microwave, And Cation Inversion Properties On Nife₂O₄ Thin Films Deposited By Pulsed Laser Ablation Deposition, C. N. Chinnasamy, S. D. Yoon, Aria Yang, Ashish Baraskar, C. Vittoria, V. G. Harris
Vincent G. Harris
First principles band structure calculations suggest that the preferential occupation of Ni2+ ions on the tetrahedral sites in NiFe₂O₄ would lead to an enhancement of the exchange integral and subsequently the Néel temperature and magnetization. To this end, we have deposited NiFe₂O₄films on MgO substrates by pulsed laser deposition. The substrate temperature was varied from 700 to 900°C at 5 mTorr of O₂ pressure. The films were annealed at 1000°C for different times prior to their characterization. X-ray diffraction spectra showed either (100) or (111) orientation with the spinel structure dependent on the substrate orientation. Magnetic studies showed a magnetization …
Microwave And Magnetic Properties Of Self-Biased Barium Hexaferrite Screen Printed Thick Films, Y. J. Chen, A. L. Geiler, T. Sakai, S. D. Yoon, C. Vittoria, V. G. Harris
Microwave And Magnetic Properties Of Self-Biased Barium Hexaferrite Screen Printed Thick Films, Y. J. Chen, A. L. Geiler, T. Sakai, S. D. Yoon, C. Vittoria, V. G. Harris
Vincent G. Harris
The interest in barium hexaferrite thick films, particularly with high remanent magnetization, is driven by the development of small planar ferrite microwave devices. We report here processing and microwave characterization of BaFe₁₂O₁₉ ferrite thick films (100-400 μm). The films were deposited on silicon and alumina substrates by screen printing, oriented under a magnetic field of 8 kOe, then annealed at 250°C and sintered at temperatures ranging from 850 to 1300°C. Scanning electron microscopy and x-ray diffraction exhibited strong crystallographic alignment of c-axis crystals perpendicular to the film plane. The magnetization measurement indicated that a typical dense film with 270 μm …
Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. Chinnasamy, J. Huang, L. Lewis, B. Latha, C. Vittoria, V. Harris
Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. Chinnasamy, J. Huang, L. Lewis, B. Latha, C. Vittoria, V. Harris
Vincent G. Harris
Ferromagnetic air-stable SmCo nanoparticles have been produced directly using a one-step chemical synthesis method. X-ray diffraction studies confirmed the formation of hexagonal SmCo5 as a dominant phase. High resolution transmission electron microscopy confirms the presence of uniform, anisotropic bladelike nanoparticles approximately 10 nm in width and 100 nm in length. Values of the intrinsic coercivity and the magnetization in the as-synthesized particles are 6.1 kOe and 40 emu/g at room temperature and 8.5 kOe and 44 emu/g at 10 K, respectively. This direct synthesis process is environmentally friendly and is readily scalable to large volume synthesis to meet the needs …
Growth And Characterization Of Thick Oriented Barium Hexaferrite Films On Mgo (111) Substrates, S. A. Oliver, S. D. Yoon, I Kozulin, M. L. Chen, C. Vittoria
Growth And Characterization Of Thick Oriented Barium Hexaferrite Films On Mgo (111) Substrates, S. A. Oliver, S. D. Yoon, I Kozulin, M. L. Chen, C. Vittoria
Carmine Vittoria
Highly oriented films of BaFe₁₂O₁₉ have been deposited onto MgO (111) substrates by pulsed laser ablation deposition. In contrast to epitaxial BaFe₁₂O₁₉ films grown on Al₂O₃ (001) substrates, these films experience an in-plane biaxial compressive stress, and do not crack or delaminate to thicknesses of at least 28 μm. X-ray diffraction, magnetometry, torque magnetometry, and ferrimagnetic resonance results all indicate excellent c-axis orientation normal to the film plane, and magnetic properties comparable to bulk values. The thickness and properties of these films approach those required for applications in low-loss self-biased nonreciprocal microwave devices
Enhanced Coercive And Remanence Fields For Cofe₂O₄ And Bafe₁₂O₁₉ Bilayers Deposited On (111) Mgo, S. D. Yoon, S. A. Oliver, C. Vittoria
Enhanced Coercive And Remanence Fields For Cofe₂O₄ And Bafe₁₂O₁₉ Bilayers Deposited On (111) Mgo, S. D. Yoon, S. A. Oliver, C. Vittoria
Carmine Vittoria
High quality epitaxial bilayer films of spinel CoFe₂O₄ (CoF) and M-type hexagonal ferrite BaFe₁₂O₁₉ (BaM) were deposited onto (111) magnesium oxide (MgO) substrate by pulsed laser ablation deposition. X-ray diffraction patterns of both BaM/CoF and CoF/BaM films showed only (0001) BaM, (111) CoF, and (111) MgO peaks. The highest coercive field of Hc=1.4 kOe was obtained for a BaM/CoF film where the CoF layer was deposited at 400°C, which was higher than typical Hc values of ∽0.4 kOe found for single layer BaM films on (111) MgO. This was less than the Hc ∽3.0 kOe found for (111) CoF films …
High-Quality Yba₂Cu₃Ox Films Prepared In Air Using Pulsed-Laser Deposition, H. Jiang, A. J. Drehman, R. J. Andrews, J. A. Horrigan, C. Vittoria
High-Quality Yba₂Cu₃Ox Films Prepared In Air Using Pulsed-Laser Deposition, H. Jiang, A. J. Drehman, R. J. Andrews, J. A. Horrigan, C. Vittoria
Carmine Vittoria
High quality YBa₂Cu₃Oₓ superconducting films have been deposited by laser deposition on yttrium stabilized cubic zirconia (YSZ) substrates using a partial pressure of air instead of oxygen. The Tc of these films was over 2° higher than films made in the same deposition system using oxygen. X-ray diffraction indicated that the films were oriented with the c axis normal to the substrate surface. The critical current densities of the films were on the order of 10⁶ A/cm² at 77 K and self-magnetic field, and the room-temperature resistivities were about 245 µὩ cm. A unique aspect of these films was that …
Microwave And Magnetic Properties Of Self-Biased Barium Hexaferrite Screen Printed Thick Films, Y. J. Chen, A. L. Geiler, T. Sakai, S. D. Yoon, C. Vittoria, V. G. Harris
Microwave And Magnetic Properties Of Self-Biased Barium Hexaferrite Screen Printed Thick Films, Y. J. Chen, A. L. Geiler, T. Sakai, S. D. Yoon, C. Vittoria, V. G. Harris
Carmine Vittoria
The interest in barium hexaferrite thick films, particularly with high remanent magnetization, is driven by the development of small planar ferrite microwave devices. We report here processing and microwave characterization of BaFe₁₂O₁₉ ferrite thick films (100-400 μm). The films were deposited on silicon and alumina substrates by screen printing, oriented under a magnetic field of 8 kOe, then annealed at 250°C and sintered at temperatures ranging from 850 to 1300°C. Scanning electron microscopy and x-ray diffraction exhibited strong crystallographic alignment of c-axis crystals perpendicular to the film plane. The magnetization measurement indicated that a typical dense film with 270 μm …