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Barium hexaferrite

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Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris Apr 2012

Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris

Anton Geiler

Barium hexaferrites (BaFe₁₂O₁₉) are especially useful for microwave/millimeter devices. Due to large ferromagnetic resonance (FMR) loss (linewidths > 2 kOe), traditional compacts of polycrystalline Ba ferrites indeed hinder the utilization of the materials for practical devices. The present experiment demonstrates that the quasi-single-crystal Ba ferrite disks can be fabricated by a single solid-state reaction technique without liquid phase participation, combining with a processing of alignment for the ferrite seed crystals. The ferrite bulks show a pure hexagonal Ba ferrite phase, an expected 4πMs of 4.48 kG, and coercivity of 10∽20 Oe along the c axis, similar to the results of a …


Alternating Target Laser Ablation Deposition Of High Quality Barium Hexaferrite Thin Films From Barium Monoferrite And Hematite Targets, A. L. Geiler, S. D. Yoon, Y. Chen, A. Yang, C. N. Chinnasamy, M. Geiler, V. G. Harris, C. Vittoria Apr 2012

Alternating Target Laser Ablation Deposition Of High Quality Barium Hexaferrite Thin Films From Barium Monoferrite And Hematite Targets, A. L. Geiler, S. D. Yoon, Y. Chen, A. Yang, C. N. Chinnasamy, M. Geiler, V. G. Harris, C. Vittoria

Vincent G. Harris

An optimized alternating target laser ablation deposition (ATLAD) technique has been developed to grow high quality barium hexaferrite (BaFe₁₂O₁₉) thin films on basal plane oriented sapphire(Al₂O₃) substrates from barium monoferrite (BaFe₂O₄) and hematite (α-Fe₂O₃) targets. Crystallographic and structural characterization results show that the films possess low c-axis dispersion of Δ ω=0.259 degrees and hexagonal terraced surface morphology. Saturation magnetization and uniaxial magnetic anisotropy field were determined to be consistent with reference data on high quality barium hexaferrite films and bulk single crystals grown by other techniques. Ferromagnetic resonance linewidth of 42 Oe was measured at 52 GHz by the shorted …


Alternating Target Laser Ablation Deposition Of High Quality Barium Hexaferrite Thin Films From Barium Monoferrite And Hematite Targets, A. L. Geiler, S. D. Yoon, Y. Chen, A. Yang, C. N. Chinnasamy, M. Geiler, V. G. Harris, C. Vittoria Apr 2012

Alternating Target Laser Ablation Deposition Of High Quality Barium Hexaferrite Thin Films From Barium Monoferrite And Hematite Targets, A. L. Geiler, S. D. Yoon, Y. Chen, A. Yang, C. N. Chinnasamy, M. Geiler, V. G. Harris, C. Vittoria

Carmine Vittoria

An optimized alternating target laser ablation deposition (ATLAD) technique has been developed to grow high quality barium hexaferrite (BaFe₁₂O₁₉) thin films on basal plane oriented sapphire(Al₂O₃) substrates from barium monoferrite (BaFe₂O₄) and hematite (α-Fe₂O₃) targets. Crystallographic and structural characterization results show that the films possess low c-axis dispersion of Δ ω=0.259 degrees and hexagonal terraced surface morphology. Saturation magnetization and uniaxial magnetic anisotropy field were determined to be consistent with reference data on high quality barium hexaferrite films and bulk single crystals grown by other techniques. Ferromagnetic resonance linewidth of 42 Oe was measured at 52 GHz by the shorted …


Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. Harris Apr 2012

Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. Harris

Vincent G. Harris

Barium hexaferrites (BaFe₁₂O₁₉) are especially useful for microwave/millimeter devices. Due to large ferromagnetic resonance (FMR) loss (linewidths > 2 kOe), traditional compacts of polycrystalline Ba ferrites indeed hinder the utilization of the materials for practical devices. The present experiment demonstrates that the quasi-single-crystal Ba ferrite disks can be fabricated by a single solid-state reaction technique without liquid phase participation, combining with a processing of alignment for the ferrite seed crystals. The ferrite bulks show a pure hexagonal Ba ferrite phase, an expected 4πMs of 4.48 kG, and coercivity of 10∽20 Oe along the c axis, similar to the results of a …


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 Apr 2012

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 …


Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris Apr 2012

Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris

Carmine Vittoria

Barium hexaferrites (BaFe₁₂O₁₉) are especially useful for microwave/millimeter devices. Due to large ferromagnetic resonance (FMR) loss (linewidths > 2 kOe), traditional compacts of polycrystalline Ba ferrites indeed hinder the utilization of the materials for practical devices. The present experiment demonstrates that the quasi-single-crystal Ba ferrite disks can be fabricated by a single solid-state reaction technique without liquid phase participation, combining with a processing of alignment for the ferrite seed crystals. The ferrite bulks show a pure hexagonal Ba ferrite phase, an expected 4πMs of 4.48 kG, and coercivity of 10∽20 Oe along the c axis, similar to the results of a …


Pulsed Laser Deposition Of Epitaxial Bafe₁₂O₁₉ Thin-Films, C. A. Carosella, D. B. Chrisey, P. Lubitz, J. S. Horwitz, P. Dorsey, R. Seed, C. Vittoria Apr 2012

Pulsed Laser Deposition Of Epitaxial Bafe₁₂O₁₉ Thin-Films, C. A. Carosella, D. B. Chrisey, P. Lubitz, J. S. Horwitz, P. Dorsey, R. Seed, C. Vittoria

Carmine Vittoria

Epitaxial thin films of barium hexaferrite (BaFe₁₂O₁₉) have been fabricated by the pulsed laser deposition technique on basal plane sapphire. Structural studies reveal the films to be predominantly single phase and crystalline, with the c axis oriented perpendicular to the film plane. The magnetic parameters deduced from vibrating sample magnetometer and ferromagnetic resonance (FMR) measurements are close to the parameters associated with bulk materials. Post annealing of the films reduced the FMR linewidth by more than a factor of 3 so that it compares reasonably well with single-crystal films. The derivative FMR linewidth was measured to be 66 Oe at …


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 Apr 2012

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 …