Temperature-stable and low loss Fe-containing dielectrics in BaO-Ln2O3-Fe2O3-Ta2O5 system

Polycrystalline samples of Ba 4 Ln 2 Fe 2 Ta 8 O 30 (Ln = La and Nd) were prepared by a high temperature solid-state reaction technique. The formation, structure, dielectric and ferroelectric properties of the compounds were studied. Both compounds are found to be paraelectrics with filled tetragonal tungsten bronze (TB) structure at room temperature. Dielectric measurements revealed that the present ceramics have exceptional temperature stability, a relatively small temperature coefficient of dielectric constant ( τ ε ) of −25 and −58 ppm/°C, with a high dielectric constant of 118 and 96 together with a low dielectric loss of 1.2 × 10 −3 and 2.8 × 10 −3 (at 1 MHz) for Ba 4 La 2 Fe 2 Ta 8 O 30 and Ba 4 Nd 2 Fe 2 Ta 8 O 30 , respectively. The measured dielectric properties indicate that both materials are possible candidates for the fabrication of discrete multilayer capacitors in microelectronic technology.