Microwave dielectric properties of Li₂M₂(MoO₄)₃ (M = Co, Ni) for LTCC applications

Abstract

Two low-firing Li 2 M 2 (MoO 4 ) 3 (M = Co, Ni) dielectrics were prepared, and their microwave dielectric properties were investigated. The XRD patterns indicated both samples crystallized in an orthorhombic structure with different space groups. The microstructures, lattice parameters, and Raman spectra of these ceramics were also systematically studied. The microwave dielectric properties were obtained with ε r ~ 9.1, Q × f ~ 34 000 GHz and τ f ~ −72 ppm/°C for Li 2 Co 2 (MoO 4 ) 3 at 840°C, ε r ~ 9.6, Q × f ~ 28 000 GHz and τ f ~ −71 ppm/°C for Li 2 Ni 2 (MoO 4 ) 3 at 660°C. With 0.05 mol% Zn substitution, excellent microwave dielectric properties (ε r ~ 10.9, Q × f ~ 56 000 GHz and τ f ~ −62 ppm/°C) can be obtained for Li 2 (Ni 0.95 Zn 0.05 ) 2 (MoO 4 ) 3 at 660°C, indicating a very promising dielectric for LTCC or ULTCC applications at high frequencies. K E Y W O R D S dielectric materials/properties, electroceramics, microwaves How to cite this article: Huang C-L, Liou J-N, Tsai M-H, Huang W-C. Microwave dielectric properties of Li 2 M 2 (MoO 4 ) 3 (M = Co, Ni) for LTCC applications. Int J Ceramic Eng Sci. 2020;2:130-139. https://doi.

Zn2+-Enhanced Lithium Magnesium Molybdate Ultralow Temperature Cofired Ceramics for Terahertz Wavefront Modulation Applications

“…For example, Professors Joseph and Varghese have developed a series of ULTCC ceramics, including CuMoO 4 (ε r = 7.9, Q × f = 53,000 GHz, τ f = −36 ppm/°C), Ag 2 O-CuMoO 4 (ε r = 9, Q × f = 37,000 GHz, τ f = −33 ppm/°C), 10Li 2 O-10Na 2 O-20K 2 O-60MoO 3 (ε r = 4.85, Q × f = 11,078 GHz, τ f = +291 ppm/°C), α-MoO 3 (ε r = 6.6, Q × f = 41,000 GHz, τ f = −25 ppm/°C), anatase TiO 2 A-30GO17 (ε r = 9.9, Q × f = 1650 GHz, τ f = +7.4 ppm/°C), and rutile TiO 2 R-30GO17 (ε r = 15, Q × f = 3300 GHz, τ f = +8.3 ppm/°C). − In addition, a series of multilayer ceramic substrates have been developed using the above materials and the tape-casting process. − However, although ULTCC ceramics with excellent microwave dielectric properties have been successfully developed, ULTCC ceramics that also possess excellent terahertz transmission properties have rarely been reported. In past studies, Li 2 Mg 2 Mo 3 O 12 (LMMO) ceramic not only possesses excellent microwave dielectric properties but also good terahertz transmission properties. , In particular, it can achieve microwave dielectric properties up to ε r = 7.9, Q × f = 43,844 GHz, τ f = −48.3 ppm/°C and terahertz transmission performance up to ε r 1 = 7.4, tanδ 1 = 0.0158, T amplitude = 0.598 when enhanced by Na + . Obviously, there is still room for further improvement in both the microwave dielectric properties and the terahertz transmission properties.…”

“…In past studies, Li 2 Mg 2 Mo 3 O 12 (LMMO) ceramic not only possesses excellent microwave dielectric properties but also good terahertz transmission properties. 32,33 In particular, it can achieve microwave dielectric properties up to ε r = 7.9, Q × f = 43,844 GHz, τ f = −48.3 ppm/°C and terahertz transmission performance up to ε r 1 = 7.4, tanδ 1 = 0.0158, T amplitude = 0.598 when enhanced by Na + . 19 Obviously, there is still room for further improvement in both the microwave dielectric properties and the terahertz transmission properties.…”