Abstract
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 typical single crystal. The FMR measurement indicates that the sample yields an anisotropy field of 16.0 kOe and a linewidth of about 300 Oe at U-band frequencies. Although the linewidth is broader than ideal Ba ferrite single crystals (Δ H < 100 Oe), it may be possible to reduce to 100 Oe by eliminating pores, cracks, local grain boundary, and nonuniformity. In terms of material preparation, we believe that it is cost effective in the production of future microwave devices.
Keywords
microwave application, barium hexaferrite, quasi single crystals, polycrystalline Ba ferrites, single solid-state reaction technique
Subject Categories
Millimeter wave devices, Anisotropy, Millimeter wave devices
Disciplines
Electromagnetics and photonics
Publisher
American Institute of Physics
Publication Date
5-1-2007
Rights Information
Copyright 2007 American Institute of Physics.
Rights Holder
American Institute of Physics
Permanent URL
Recommended Citation
Chen, Yajie; Geiler, Anton L.; Chen, Taiyang; Sakai, Tomokazu; Vittoria, C.; and Harris, V. G., "Low-loss barium ferrite quasi-single-crystals for microwave application" (2007). Electrical and Computer Engineering Faculty Publications. Paper 68. http://hdl.handle.net/2047/d20002239
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low_loss_barium_fig1.zip (11 kB)Figure 1
low_loss_barium_fig2.zip (927 kB)
Figure 2
low_loss_barium_fig3.zip (32 kB)
Figure 3
low_loss_barium_fig4.zip (25 kB)
Figure 4
low_loss_barium_fig5.zip (6 kB)
Figure 5
Notes
Originally published in Journal of Applied Physics 101, 09M501 (2007). DOI:10.1063/1.2709726 (http://dx.doi.org/10.1063/1.2709726).