A Novel Magnetodielectric Solid Solution Ceramic 0.4 LiFe 5 O 8 –0.6 Li 2 MgTi 3 O 8 with Excellent Microwave Dielectric Properties

In this study, a novel spinel solid solution ceramic of 0.4 LiFe 5 O 8 –0.6 Li 2 MgTi 3 O 8 (0.4 LFO –0.6 LMT ) has been developed and investigated. It is found that the 40 mol% LiFe 5 O 8 and 60 mol% Li 2 MgTi 3 O 8 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% H 3 BO 3 – 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.