A ferromagnetic ferroelectric cofired ceramic for hyperfrequency

A series of composite materials were prepared by cofired ceramics technology with 0.8 Pb ( Ni 1 ∕ 3 Nb 2 ∕ 3 ) O 3 - 0.2 Pb Ti O 3 (PNNT) and Ba 2 Zn 1.2 Cu 0.8 Fe 12 O 22 as two components. The weight fraction of PNNT, signed as x , varied from 0.1 to 0.9. The coexistence of two phases in the composites was observed directly via scanning electron microscopy, and proved by x-ray diffraction spectra. The composites show excellent cofiring behavior. According to ferromagnetic and ferroelectric hysteresis loops, the composites exhibit both ferromagnetic and ferroelectric properties over a wide composition range ( x = 0.1 - 0.9 ) . The composites have excellent magnetic and dielectric properties in hyperfrequency. With the rise of x , permeability decreases and permittivity increases. The permittivity resonant peak shifts to higher frequency with the decrease of x . Maxwell-Garnett equations are used to fit the permeability and permittivity of the composites. It can give valuable predication for composite material design. These composites are promising for applying in truly integrated passive filter in hyperfrequency.