Enhanced efficiency C-axis textured M-type barium ferrite for realization of self-biased circulators
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Enhanced efficiency C-axis textured M-type barium ferrite for realization of self-biased circulators Yu Wang1 · Le Chang2 · Yingli Liu1 · Huaiwu Zhang1 · Qian Liu1 · Chongsheng Wu1 · Liwen Gao1 Received: 5 December 2017 / Accepted: 10 April 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018
Abstract This paper presents the synthesis and realization of the C-axis textured M-type barium ferrite B aScxFe12−xO19 (x = 0.1, 0.3, 0.6, 0.8, 1.0) using the solid-state method. Among this samples, the B aScxFe12−xO19 with x = 0.1 ferrite exhibits preferable magnetic properties with the saturation magnetization of ~ 4700 Gauss and squareness ratio of 0.65, which is suited for the realization of self-biased circulator design. Results of the SEM reveal that the S c3+ has negligible effect on the crystal morphology. The measured results for the vibrating sample magnetometer indicate that increasing x of the induced S c3+ yields decreasing the magneto-crystalline anisotropy field, saturation magnetization, coercivity, and reduces the squareness ratio. Besides, influence of Sc3+ on dielectric constant also have be investigated.
1 Introduction Circulators are nonreciprocal media which represent the key element of full-duplex telecommunication systems and radars. A circulator is conventionally realized based on the asymmetric magnetic permeability tensor provided by the magnetically-biased ferrites. However, such materials suffer from bulkiness which restricts the high frequency applications of ferrite-based circulators. The YIG-based circulators represent alternatives for ferrite-based circulators at microwave frequencies, which may be used at millimeter wave frequencies with stronger external field [1]. However, stronger external field represents larger circulator size, and therefore, limits the millimeter wave application of such structures. The hexagonal ferrite presents fascinating properties which may be used for the millimeter wave applications of circulators. Comparing with the spinel and garnet, the hexagonal ferrite possessed high internal magneto-crystalline anisotropy field, which is the key factor for the self-biased passive nonreciprocal structures. The operation frequency ω * Yingli Liu [email protected] 1
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
Science & Technology Development Department, China National Machinery Industry Corporation, Beijing 100080, China
2
in such materials reads ω = γ(HA + H0), where HA is the magneto-crystalline anisotropy field, and H0 denotes the external magnetic field. As a result, the anisotropy magnetic field intrinsically provides a self-biased magnetic field so that the material may be applied at millimeter wave frequencies requiring much smaller applied field than the garnet. The M-type barium ferrite represents a hexagonal ferrite, which have been widely used as permanent magnetic materials [2] and perpendicular magnetic recordi
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