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Microwave Dielectric Properties Trends in a Solid Solution (Bi 1− x Ln x ) 2 Mo 2 O 9 (Ln=La, Nd, 0.0≤ x ≤0.2) System
Author(s) -
Zhou Di,
Randall Clive A.,
Wang Hong,
Pang LiXia,
Yao Xi
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03307.x
Subject(s) - temperature coefficient , materials science , ceramic , dielectric , analytical chemistry (journal) , solid solution , permittivity , monoclinic crystal system , sintering , phase (matter) , microwave , atmospheric temperature range , mineralogy , dielectric loss , doping , crystal structure , crystallography , chemistry , thermodynamics , metallurgy , composite material , physics , optoelectronics , organic chemistry , chromatography , quantum mechanics
The influence of La 3+ and Nd 3+ substitution for the Bi 3+ cations in the low‐firing Bi 2 Mo 2 O 9 system is considered in regard to the sintering behavior, density, phase composition, and microwave dielectric properties. All the compositions can be sintered to high densities in temperature range of 620°–680°C. In (Bi 1− x Ln x ) 2 Mo 2 O 9 (Ln=La, Nd) ceramics, when x ≤0.2 the solid solution is within a monoclinic phase ( P 2 1 / n ) and the phase had an increase in melting temperature with the doping. In the La substitution case, the (Bi 0.8 La 0.2 ) 2 Mo 2 O 9 ceramics had the best microwave dielectric properties with a permittivity of 32.7, a Qf value ( f =resonant frequency, Q =1/dielectric loss at f ) of 13 490 GHz and a temperature coefficient of −4.6 ppm/°C. With the Nd‐substituted samples, the (Bi 0.9 Nd 0.1 ) 2 Mo 2 O 9 ceramics had the best microwave dielectric properties with a permittivity of 33.9, a Qf value of 15 200 GHz and a temperature coefficient of +8.05 ppm/°C. The substitution of La and Nd can effectively modify the microwave dielectric properties of Bi 2 Mo 2 O 9 ceramic and in particular adjust the temperature coefficient to near zero. The (Bi 1− x Ln x ) 2 Mo 2 O 9 (Ln=La, Nd) ceramics are very interesting new materials for an ultralow‐temperature cofired ceramics technology that is compatible with Al metal electrodes.