High permittivity and near-zero Tε dielectrics Ca0.36Sr0.64TiO3-Li0.5Nd0.5TiO3 for multilayer ceramic capacitors

The microstructure and dielectric properties of (1-x)Ca0.36Sr0.64TiO3-xLi(0.5)Nd(0.5)TiO(3) (0 <= x <= 1) [abbreviated as (1 - x) CST-xLNT] solid solutions were investigated in this study. X-ray diffraction results showed that the samples exhibited a single cubic phase with x <= 0.5, whereas increasing LNT content resulted in a structural change from cubic to tetragonal phase in when x > 0.5. The permittivity (epsilon(r)) decreased with increasing x, while the dielectric loss (tan delta) increased and then decreased at x = 1.0. The temperature dependence of epsilon(r) and tan delta at 1MHz for the (1 - x)CST-xLNT ceramics was also investigated. The temperature coefficient of the permittivity (T-epsilon) increased from highly negative values to positive values with increasing x. A near-zero T-epsilon was achieved at x = 0.57. Optimised dielectric properties were estimated to be epsilon(r) = 227, tan delta = 0.043 and T-epsilon = 12 ppm/degrees C. Therefore, the 0.43CST-0.57LNT ceramic is proposed as a promising candidate material for multilayer ceramic capacitors with good temperature stability and high capacitance. (C) 2015 The Japan Society of Applied Physics