AxByTiO3

AxByTiO3 is a generalized chemical formula used in materials science to describe a family of mixed titanate perovskites in which the A-site of the perovskite lattice is occupied by two cation species, A and B, in fractions x and y, while titanium typically occupies the B-site of the oxide framework (TiO3). The exact arrangement and whether B-site substitution occurs depend on the chosen elements and synthesis. When x + y is close to 1, the composition often forms a single-phase solid solution; deviations can lead to secondary phases or ordering phenomena.

Structure and composition: In the ideal perovskite structure, AB O3 consists of corner-sharing BO6 octahedra with a large A-site cavity. In AxByTiO3, substitutions on the A-site modify lattice parameters, tilting of the BO6 framework, and overall symmetry. Substituting on the B-site (for example, partial replacement of Ti) can further alter bond lengths, electronic structure, and ferroelectric behavior. The tolerance factor, determined by ionic radii, helps predict stability and distortion.

Synthesis and phase behavior: Common preparation routes include solid-state synthesis from oxides or carbonates, as well as sol-gel or combustion methods. High-temperature sintering promotes phase formation and crystallization. Compositional ranges exhibit solid solution limits; certain compositions may experience phase separation, ordering, or enhanced defect formation depending on temperature and atmosphere.

Properties and applications: Dielectric, ferroelectric, and piezoelectric responses in AxByTiO3 materials are highly composition-dependent. These titanates are explored for capacitors, actuators, sensors, and energy-related devices, with particular interest in lead-free variants. Doping and cation ordering can influence leakage currents, fatigue behavior, and aging.

See also: perovskite, ABO3 titanates, solid solutions, ferroelectric materials.