Pyroelectric Performances of Relaxor‐Based Ferroelectric Single Crystals and their Applications in Infrared Detectors

Relaxor-based ferroelectric single crystals(i.e.,lead magnesium niobate-lead titanate(PMNT),Mn-doped PMNT, ternary lead indium niobate-lead magnesium niobate-lead titanate(PMNT)and Mn-doped PIMNT)exhibit a high piezoelectric performance and superior pyroelectric properties.The pyroelectric coefficients of 15.3×10-4C/m2 K and 17.2×10-4C/m2 K were obtained for PMN-0.26PT and Mn-doped PMN-0.26PT,respectively.The dielectric loss of binary and ternary relaxor-based single crystals decreases from 0.3%to 0.05%due to Mn ions doping,enhancing the detectivity figure of merit(Fd)from 15.3×10-5Pa-1/2to 40.2× 10-5 Pa-1/2 for Mn-doped PMN-0.26PT.The Fdof Mn-PIMNT(23/47/30)is 19.5×10-5Pa-1/2.Furthermore,the Curie temperature is 253℃for PIMNT(41/17/42)and 179℃for Mn-doped PIMNT(23/47/30),respectively.By using the Mn-doped PMNT single crystals as sensitive element and multi-walled carbon nanotubes as absorbing layer,we can obtain the superior infrared detector.The specific detectivity of Mn-doped PMNT-based detector is 3.0×109 cm·Hz1/2/W at 4Hz and 2.21×109 cm·Hz1/2/W at 10Hz,respectively,which are four times greater than that of LiTaO3-based detector.