A Novel Magnetodielectric Solid Solution Ceramic 0.4LiFe₅O₈–0.6Li₂MgTi₃O₈ with Excellent Microwave Dielectric Properties

Abstract

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.

Order–Disorder Phase Transition and Magneto‐Dielectric Properties of (1−x)LiFe5O8–xLi2ZnTi3O8 Spinel‐Structured Solid Solution Ceramics

“…Moreover, the multiphase cofired ceramics usually show compromised properties rather than an optimization of each component. Therefore, to develop novel materials with outstanding comprehensive properties, the solid solution method, as an important solution to improve the performance of materials through compositional design, attracts more and more concerns …”

“…Therefore, to develop novel materials with outstanding comprehensive properties, the solid solution method, as an important solution to improve the performance of materials through compositional design, attracts more and more concerns. [7][8][9] The spinel structure with the typical chemical formula of AB 2 O 4 belongs to a cubic crystalline system with a large unit cell containing 8A, 16B, and 32 oxygen atoms. The oxygen ions form a cubic close-packed array with tetrahedrally (T d ) and octahedrally (O h ) coordinated interstices.…”

Preparation and microwave dielectric properties of B2O3 bulk

“…Many methods have been developed to lower the sintering temperature of ceramics, such as using fine ceramic powder, liquid phase sintering, spark plasma sintering, field assisted sintering, flash sintering, cold sintering and etc. 11 Many sintering aids with low melting points have been used in the sintering of microwave dielectric ceramics, such as B 2 O 3 , 12-14 H 3 BO 3 , [15][16][17] LiF, 18 MgF 2 , 14,19 CaF 2 20 , and glass 21 . For the typical liquid phase sintering, a suitable sintering aid with low melting point is added into the ceramic powder, and the ceramic is soluble in the liquid sintering aid above its melting point.…”

“…22 Among the sintering aids for microwave dielectric ceramics, B 2 O 3 has been widely used because of its very low melting point. [12][13][14] It is worthy to note that H 3 BO 3 is another common sintering aid, [15][16][17] while B 2 O 3 is the liquid phase that really acts due to the decomposition of H 3 BO 3 into B 2 O 3 . Furthermore, B 2 O 3 has also been widely used in the microwave dielectric materials of boron-based ceramics and glass.…”