Phase transition monitoring and temperature sensing via FIR technology in Bi/Sm‐codoped KNN transparent ceramics
Ping Zhou, Fangyuan Yu, Xiangfu Zeng, Min Gao, Chunlin Zhao, Cong Lin, Tengfei Lin, Laihui Luo, Jinfeng Lin, Xiao Wu
Abstract
Abstract The phase transition temperature (e.g., that of orthorhombic‐tetragonal T O‐T ) of relaxor ferroelectrics are commonly obtained through electrical method (i.e., temperature dependence of dielectric constant), and the samples need to be coated with metal electrode and tested by a sophisticated impedance analyzer. This contact measuring method is inefficient, inconvenient and easy to damage the sample surface, inapplicable to transparent ferroelectrics. Here, we successfully fabricated Bi/Sm co‐doped K 0.5 Na 0.5 NbO 3 transparent ceramics with photoluminescent behavior and relaxor‐like ferroelectricity, which simultaneously realized T O‐T monitoring and temperature sensing via fluorescence intensity ratio (FIR) technology. This simple, rapid, noncontact and nondestructive optical way displays small T O‐T deviation (merely 0.78%) compared to the electrical method. And the temperature‐dependent optical characteristics and coercive electric field all present abrupt changes, whose abnormal temperature regions are in accordance with that around T O‐T . In addition, the maximum absolute sensitivity and relative sensitivity of the ceramics reach 0.0072 K −1 (at 533 K) and 0.0111 K −1 (at 453 K), respectively, exhibiting superior optical temperature sensing performance. The tactical use of FIR technology is of great significance for widening the applications of luminescent‐ferroelectric transparent ceramics.