In this work the pyroelectric performances of relaxor-based ferroelectric single crystals (PMN-PT, Mn-doped PMN-PT, ternary PIN-PMN-PT and Mn-doped PIN-PMN-PT) are reported. The crystals show high pyroelectric coefficients (p), especially for PMN-0.26PT and Mn-doped PMN-0.26PT with values as high as 15.3×10(-4) C/m~2K and 17.2×10~(-4) C/m~2K respectively. A co-design methodology of the macroscopic symmetry constraint controlling spontaneous polarization order parameter and dipole defects pinning controlling dynamic loss was established to control growth of crystals and reveal the physical mechanism of low dielectric loss for Mn-doped crystals. Dielectric losses of binary and ternary relaxor-based single crystals are depressed to 0.05 %, enhancing the detectivity figure of merit (F_d) up to 40.2× 10~(-5) Pa~(-1/2) for Mn-doped PMN-0.26PT. The simulations were carried out for the performances of relaxor-based single crystal detectors in order to fabiricate high performance detectors. The results show that relaxor-based ferroelectric single crystals have great advantages compared with the conventional LiTaO_3 and DTGS in the low frequency range. By using Mn-doped PMNT single crystals as sensitive element and the multi-walled carbon nanotubes as absorbing layer, the outstanding infrared detectors were achieved. The specific detectivity (D~*) of Mn-doped PMNT-based detector is up to 3.01×10~9 cmHz~(1/2)/W (at 2 Hz) and 2.21×10~9 cmHz~(1/2)AV (10 Hz, 500 K, 25 °C) respectively, four times higher than that of LiTaO_3-based detectors.
展开▼
