Microstructure and Dielectric Properties of Barium Strontium Magnesium Niobate

Abstract

Dielectric properties and their related microstructural characteristics in solid solutions of (1 -x)Ba(Mg 1/3 Nb 2/3 )O 3 -xSr(Mg 1/3 Nb 2/3 )O 3 (BMN-SMN, or BSMN) were investigated by measuring the relative permittivity ( r ), Q values, and temperature coefficient of resonator frequency ( f ), and by observing microstructure using transmission electron microscopy. When the tolerance factor (t) was >0.99 in BSMN with composition 0 < x < 0.5, where the tilting of oxygen octahedra was not involved, the microstructure included only 1:2 ordered phase. In the region where 0.99 > t > 0.97 with 0.7 < x < 1.0, the phase due to the antiphase tilting of oxygen octahedral, the disordered phase, and the 1:2 ordered phase were also present. In a few of the grains, core-shell-type structures, whose main components were dislocations and stacking faults, were found in the solid solution of BSMN.

Tailoring the order–disorder transition and microwave dielectric properties of Ba[(Ni0.6Zn0.4)1/3Nb2/3]O3 ceramics by Mg-substitution

“…The variation of ordering degree can be explained in terms of volume fraction of ordering domains. The 1:2 ordering of Ni/Zn/Mg and Nb cations can develop along any one of the four equivalent {111} crystal planes, when they impinge each other, ordering domains separated by twin boundaries or antiphase boundaries (APBs) are produced [27]. The dark-field TEM images of Ba[(Ni 0.6Àx/2 Zn 0.4Àx/2 Mg x ) 1/3 Nb 2/3 ]O 3 ceramics are illustrated in Fig.…”

Lattice dynamics and phonon characteristics of complex perovskite microwave ceramics

“…Subsequently, new models were developed by Nagai et al [41] to study the octahedral tilting in the 1:2 ordered structures. Two regions in Ba 1− x Sr x (Mg 1/3 Nb 2/3 )O 3 (BSMN) ceramics were recognised by Lee et al [37, 42]: the 1:2 ordered trigonal structures without/with octahedral tilting [43].…”

Effects of Postdensification Annealing on Microwave Dielectric Properties of Ba([Mg1−xCox]1/3Nb2/3)O3 Ceramics

“…For instance, much work has been carried out on Ba(Zn 1/3 Nb 2/3 )O 3 , which indicates a good combination of microwave dielectric properties: e r = 41, Q 9 f~55,670 GHz, s f = 27 ppm/°C. 21,22 However, such substitutions involve more complicate structure (octahedra tilting) and microstructure. 16,17 On the other hand, Ba(Mg 1/3 Nb 2/3 )O 3 has higher Q 9 f value (Q 9 f~56,000 GHz), but its unacceptably high s f (33 ppm/ o C) needs to be tuned for practical applications.…”

“…19,20 2+ , the s f can be tuned toward negative through zero. 21,22 However, such substitutions involve more complicate structure (octahedra tilting) and microstructure. The Co 2+ substitution for Mg 2+ was reported to tune the s f to near-zero.…”