The c-axis oriented Ba 3 Co 2 Fe 24 O 41 (Co 2 Z) ceramic with high permeability was successfully prepared by reactive templated grain growth (RTGG) method using reactive template BaFe 12 O 19 (BaM) and complementary Ba 2 Co 2 Fe 12 O 22 (Co 2 Y). The microstructure and magnetic property of the textured ceramic sample in different orientations were investigated. The sample presents both structural and magnetic anisotropic characteristics. The obtained (00h) textured Co 2 Z ceramic exhibits a favorable combination of easy magnetization plane orientation, high initial permeability of 19.0±1.2 (much higher than that from conventional ceramic method (CCM) ( i =12)), and high cutoff frequency (f r >1GHz), indicating the potential for high frequency application in novel electronic devices.

In this study, a novel spinel solid solution ceramic of 0.4LiFe5O8–0.6Li2MgTi3O8 (0.4LFO–0.6LMT) has been developed and investigated. It is found that the 40 mol% LiFe5O8 and 60 mol% Li2MgTi3O8 are fully soluble in each other and a disordered spinel phase is formed. The ceramic sample sintered at 1050°C/2 h exhibits both good magnetic and dielectric properties in the frequency range 1–10 MHz, with a permeability between 29.9~14.1 and magnetic loss tangent between 0.12~0.67, permittivity between 16.92~16.94 and dielectric loss tangent between 5.9 × 10−3–2.3 × 10−2. The sample also has good microwave dielectric properties with a relative permittivity of 16.1, a high quality factor (Q × f) ~28 500 GHz (at 7.8 GHz). Furthermore, 3 wt% H3BO3–CuO (BCu) addition can effectively lower the sintering temperature to 925°C and does not degrade the magnetodielectric properties. The chemical compatibility with silver electrode indicates that this kind of ceramics is a good candidate for the low‐temperature cofired ceramic (LTCC) application.

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Magneto-dielectric composite ceramics Ba 3 Co 2 Fe 24 O 41 /SrTiO 3 (Co 2 Z/STO) loading with high volume fraction of hexaferrite Co 2 Z (f Co2Z = 60%-95%) are successfully prepared by a hybrid process. The microstructures with homogeneously dispersed constituent grains are observed in these composites. The composites loading with 60%-80% hexaferrite possess stable magneto-dielectric properties in the frequency range from 10 MHz to 1 GHz with both low dielectric loss and magnetic loss. For the composite loading with 60% Co 2 Z, the relative permittivity is 28.08 and permeability is 4.46 (at 10 MHz), the dielectric loss tangent keeps below 0.009 within the frequency range from 10 MHz to 1 GHz. Also, it possesses a magnetic loss tangent of 0.006 and 0.144 at 50 MHz and 1 GHz, respectively, which are much lower than 0.056 and 1.242 of the single Co 2 Z phase at the same frequency. These excellent properties indicate that the low-loss Co 2 Z/STO composite ceramic is a new kind of multifunctional magneto-dielectric material with potential for high-frequency electromagnetic device applications.

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