Linrong Yang

Scale Effects of Low‐Dimensional Relaxor Ferroelectric Single Crystals and Their Application in Novel Pyroelectric Infrared Detectors

Scaling effects of low-dimensional relaxor ferroelectric single crystals have induced large delocalization of domain switching, leading to a dramatic increase in pyro-electric performances by 2-5.5 times, and promoting the detectivity of fabricated pyroelectric detectors to an international leading level of 2.21 × 10(9) cmHz(1/2) /W at 10 Hz, 4 times higher than that of commercial LiTaO3 -based detectors.

Enhancement in nanoscale electrical properties of lead zirconic titanate island fabricated by focused ion beam

Lead zirconic titanate (PZT) microscale island (1 μm–100 nm) was fabricated by focused ion beam before its crystallization, followed by the annealing treatment at the crystallization temperature. Local electrical properties were evaluated by piezoresponse force microscopy technique. Compared to the PZT island fabricated after crystallization, the result shows that there is noticeable enhancement in nanoscale electrical properties of PZT island fabricated before crystallization, especially when the island size decreases. Raman spectra and Kelvin force microscopy result both show that there are little degradations on the PZT surface after this amorphous etching process. The mechanism will be discussed in this paper. These results are very beneficial to the development of the ferroelectric film applications in the dynamic random access memory, ferroelectric random access memory, and micro-electro-mechanical system field.

Absolute determination of optical constants of three transition metals using reflection electron energy loss spectroscopy

The optical constants, n and k, of three transition metals (Cr, Co, and Pd) were determined from the measured reflection electron energy-loss spectroscopy (REELS) spectra, covering the spectral energy range from visible to vacuum ultraviolet. To do this, a spectral data analysis technique [Xu et al., Phys. Rev. B 95, 195417 (2017)], which combines a sophisticated Monte Carlo simulation for modelling the experimental REELS spectrum and the simulated annealing algorithm for the determination of the true energy loss function (ELF) was adopted. The validity of the obtained ELFs was discussed by comparing with the previous data derived by optical methods and by applying the oscillator strength and the perfect screening-sum rules. Besides, the consistency of the calculated data was evaluated for three in situ measurements for each sample at three primary energies. The complex dielectric function, the refractive index n and the extinction coefficient k were then derived from the obtained ELF via the analytical K...

Enhanced pyroelectric properties and thermal stability of Mn-doped 0.29Pb(In1/2Nb1/2)O3-0.29Pb(Mg1/3Nb2/3)O3–0.42PbTiO3 single crystals

The pyroelectric properties and thermal stability of a [001]-oriented tetragonal 1 mol. % Mn-doped 0.29Pb(In1/2Nb1/2)O3-0.29Pb(Mg1/3Nb2/3)O3-0.42PbTiO3 [Mn-PIN-PMN-PT(29/29/42)] ternary single crystal were investigated. The single crystal exhibited a high pyroelectric coefficient of p = 6.0 × 10−4 C m−2 K−1 and figures of merit (FOMs) at 1 kHz for a current responsivity of Fi = 2.4 × 10−10 mV−1, a voltage responsivity of Fv = 0.08 m2 C−1, and a detectivity of Fd = 19.8 × 10−5 Pa−1/2 which were weakly dependent on frequency. These all increased linearly upon increasing temperature to 120 °C. Furthermore, the values of p for the ternary single crystal were weakly dependent on thermal annealing temperatures (Ta), maintaining over 75% of the original value at Ta < 160 °C, which was 70 °C higher than that of the [111]-oriented rhombohedral 1 mol. % Mn-doped 0.73Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 [Mn-PMN-PT(73/27)] binary single crystal. These excellent pyroelectric properties, together with good thermal stability and wide operational temperature, make the [001]-oriented tetragonal Mn-PIN-PMN-PT(29/29/42) single crystal a promising candidate for pyroelectric detection and thermal imaging applications.The pyroelectric properties and thermal stability of a [001]-oriented tetragonal 1 mol. % Mn-doped 0.29Pb(In1/2Nb1/2)O3-0.29Pb(Mg1/3Nb2/3)O3-0.42PbTiO3 [Mn-PIN-PMN-PT(29/29/42)] ternary single crystal were investigated. The single crystal exhibited a high pyroelectric coefficient of p = 6.0 × 10−4 C m−2 K−1 and figures of merit (FOMs) at 1 kHz for a current responsivity of Fi = 2.4 × 10−10 mV−1, a voltage responsivity of Fv = 0.08 m2 C−1, and a detectivity of Fd = 19.8 × 10−5 Pa−1/2 which were weakly dependent on frequency. These all increased linearly upon increasing temperature to 120 °C. Furthermore, the values of p for the ternary single crystal were weakly dependent on thermal annealing temperatures (Ta), maintaining over 75% of the original value at Ta < 160 °C, which was 70 °C higher than that of the [111]-oriented rhombohedral 1 mol. % Mn-doped 0.73Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 [Mn-PMN-PT(73/27)] binary single crystal. These excellent pyroelectric properties, together with good thermal stability and...

Residual stress and interface effect on dielectric mechanisms in poled ultrathin relaxor ferroelectric single crystals

We have investigated the dielectric performances and mechanism of super-thin Mn-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals, exhibiting significantly different dielectric behaviors compared with thick wafer. Dramatic decrease by 5 times and large frequency dispersion of permittivity, changed diffuse degree of phase transition, dielectric loss anomaly with frequency and dielectric performances with direct-current electric field for thin wafers are observed, proving the existence of large surface residual stress and interface effects. Additionally, a theoretical model of low-permittivity and low-ferroelectric surface damage layers is concurrently proposed. These observations have important implications for actual performances of thin wafers applied in practical devices.