Improved Pyroelectric Properties of CaBi ₄ Ti ₄ O ₁₅ Ferroelectrics Ceramics by Nb / Mn Co‐Doping for Pyrosensors

Abstract

The pyroelectric properties of Nb(Mn)‐doped and Nb/Mn co‐doped CaBi 4 Ti 4 O 15 ( CBT ) bismuth layer‐structured ferroelectric ceramics were investigated. It was found that Nb/Mn co‐doping resulted in stronger enhancement of pyroelectric properties than that of single Nb or Mn doping. The mechanism of doping effect was explained by the distortion of the [ BO 6 ] octahedra induced by the doped Nb and Mn cations occupying the B‐site of the pseudoperovskite structure. A large pyroelectric coefficient of 84.4 μC/m 2 K was obtained at room temperature for Nb/Mn co‐doped CBT ( CBTN ‐Mn) ceramics, higher than that of pure, Nb or Mn‐doped counterparts, being on the order of 35.9, 58.2, 44.0 μC/m 2 K, respectively. The enhanced pyroelectric coefficient together with reduced dielectric constant (99) and dielectric loss (0.002) led to greater improvement of figures of merit ( FOM s), including FOM s for voltage responsivity ( F v ~ 3.95 × 10 −2 m 2 /C) and detectivity ( F d ~ 2.44 × 10 −5 Pa −1/2 ), in CBTN ‐Mn ceramics. Furthermore, the temperature variations of F v and F d were found to be 24% and 68%, respectively, over a broad temperature range from room temperature to 350°C, making CBTN ‐Mn ceramics potential candidate for high‐temperature pyroelectric devices.