Dual‐Channel Dielectric Tunability in Highly Textured BaTi 0.99 Fe 0.01 O 3− δ Ceramics With Micro‐Twin Boundary

Dielectric tunability is widely used in numerous electronic devices, including wavelet filters, lens antennae, and varactors. However, a dielectric device often has only one tunable dielectric constant range, confining the integration of a multi‐frequency electronic circuit. Herein, a new kind of dielectric tunable textured BaTi 0.99 Fe 0.01 O 3− δ ceramics with micro‐twin boundaries is proposed for the dual‐channel controllable dielectric constants. The relative tunability with the acceptable figure of merit is as large as 76% in the crossover channel, which is superior to that of the most state‐of‐the‐art Ba x Sr 1 − x TiO 3 counterparts. This new design strategy offers the possibility of dual‐channel filters in one dielectric device controlled by external electric fields. The required external electric field is moderate with the help of reversible micro twins, which is confirmed by first‐principles studies. The static magnetic field interference on the dielectric constant is also evaluated, showing the frequency stability of dielectric tunability in a range between 5k and 1 m Hz.