Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show tha...Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show that PZN- 7% PT single crystals have excellent SAW properties,such as low phase velocities,very high electromechanical coupling coefficients and small power flow angles.It is also found that the SAW properties strongly depend on the propagation direction and the characteristic curves of SAW phase velocity,and the electromechanical coupling coefficients are symmetric with respect to θ =90°.Considering all related factors,the X-cut PZN-7%oPT single crystal has the best performance.Based on our results,the X-cut PZN-7%PT single crystals poled along [011]c are an excellent candidate for ultra-wide bandwidth low-frequency SAW devices.展开更多
The propagation characteristics of shear horizontal waves in[001]𝑑,[011]𝑑and[111]𝑑direction polarized 0.72Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.28PbTiO_(3)(PMN-0.28PT)piezoelectric single crystals/polyme...The propagation characteristics of shear horizontal waves in[001]𝑑,[011]𝑑and[111]𝑑direction polarized 0.72Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.28PbTiO_(3)(PMN-0.28PT)piezoelectric single crystals/polymer periodic laminated composites are studied by using the global matrix method.The numerical results show that the piezoelectric effect has a significant influence on the bandgap width of the composite structure containing[011]𝑑and[111]𝑑poled PMN-0.28PT,but little effect on the band structure of the system containing[001]𝑑poled single crystal.In addition,the first bandgap(FBG)width of the composite structure depends strongly on the poling directions when the filling fraction of PMN-0.28PT is larger than 0.5,and its FBG starting frequency displays no distinct difference among the three polarization directions at all filling fractions.The reported results provide valuable guidelines for designing filters and transducers made of composite structures containing relaxor-based ferroelectric single crystals.展开更多
An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photolum...An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photoluminescence(UC−PL)around 524 nm and 545 nm depends on temperature.The operating temperature range and the maximum sensitivity of Er ^(3+)/Yb ^(3+)co−doped Bi_(3)TiNbO_(9) ceramics are 123–693 K and 0.0032 K^(−1),respectively.BTN:Er3+/Yb3+ceramic has good thermal,physical and chemical stability,great UC−PL intensity and low cost fabrication.The results imply that Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbO9 ceramic is promising for applications in wide-temperature-range sensors.展开更多
Pyroelectric measurements are conducted during zero-field heating in [001],[110] and [111] poled 0.69Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.31PbTiO_(3) single crystals.Compared to the room-temperature-poled samples,the crystals ...Pyroelectric measurements are conducted during zero-field heating in [001],[110] and [111] poled 0.69Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.31PbTiO_(3) single crystals.Compared to the room-temperature-poled samples,the crystals poled by using the field cooling method show broad but well recognizable pyroelectric current peaks near 190℃,which is much higher than the Curie point (126℃) of the crystal.We propose that this peak of the crystals poled by field-cooling above the Curie point is ascribed to the order-disorder transition of the dipoles in polar nano-regions formed at the Burns temperature.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 50972034the Program of the Ministry of Education of China for New Century Excellent Talents in University under Grant No NCET-06-0345+1 种基金the Postdoctoral Science Research Developmental Foundation of Heilongjiang Province under Grant No LBH-Q06068the Program of BRET and Excellent Team in Harbin Institute of Technology,SRF for ROCS,SEM,and NIH under Grant No P41-EB21820.
文摘Surface acoustic wave (SAW) propagation in relaxor-based ferroelectric single crystals 0.93Pb(Zn_(1/3)Nb_(2/3))O_(3)- 0.07Pb TiO_(3) (PZN- 7%PT ) poled along [011]c has been analyzed theoretically.The results show that PZN- 7% PT single crystals have excellent SAW properties,such as low phase velocities,very high electromechanical coupling coefficients and small power flow angles.It is also found that the SAW properties strongly depend on the propagation direction and the characteristic curves of SAW phase velocity,and the electromechanical coupling coefficients are symmetric with respect to θ =90°.Considering all related factors,the X-cut PZN-7%oPT single crystal has the best performance.Based on our results,the X-cut PZN-7%PT single crystals poled along [011]c are an excellent candidate for ultra-wide bandwidth low-frequency SAW devices.
基金Supported by the National Basic Research Program of China under Grant No 2013CB632900,the National Natural Science Foundation of China under Grant No 50602009,Program of the Ministry of Education of China for New Century Excellent Talents in University under Grant No NCET-06-0345,Postdoctoral Science Research Developmental Foundation of Heilongjiang Province under Grant No LBH-Q06068.
文摘The propagation characteristics of shear horizontal waves in[001]𝑑,[011]𝑑and[111]𝑑direction polarized 0.72Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.28PbTiO_(3)(PMN-0.28PT)piezoelectric single crystals/polymer periodic laminated composites are studied by using the global matrix method.The numerical results show that the piezoelectric effect has a significant influence on the bandgap width of the composite structure containing[011]𝑑and[111]𝑑poled PMN-0.28PT,but little effect on the band structure of the system containing[001]𝑑poled single crystal.In addition,the first bandgap(FBG)width of the composite structure depends strongly on the poling directions when the filling fraction of PMN-0.28PT is larger than 0.5,and its FBG starting frequency displays no distinct difference among the three polarization directions at all filling fractions.The reported results provide valuable guidelines for designing filters and transducers made of composite structures containing relaxor-based ferroelectric single crystals.
基金by the National Natural Science Foundation of China under Grant No 10704021the Natural Scientific Research Innovation Foundation at the Harbin Institute of Technology(2009055).
文摘An optical temperature sensor based on infrared-to-visible upconversion emission in Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbØ9(BTN)ceramics is reported.The fluorescence intensity ratio of the green upconversion photoluminescence(UC−PL)around 524 nm and 545 nm depends on temperature.The operating temperature range and the maximum sensitivity of Er ^(3+)/Yb ^(3+)co−doped Bi_(3)TiNbO_(9) ceramics are 123–693 K and 0.0032 K^(−1),respectively.BTN:Er3+/Yb3+ceramic has good thermal,physical and chemical stability,great UC−PL intensity and low cost fabrication.The results imply that Er ^(3+)/Yb ^(3+)co−doped Bi3TiNbO9 ceramic is promising for applications in wide-temperature-range sensors.
文摘Pyroelectric measurements are conducted during zero-field heating in [001],[110] and [111] poled 0.69Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.31PbTiO_(3) single crystals.Compared to the room-temperature-poled samples,the crystals poled by using the field cooling method show broad but well recognizable pyroelectric current peaks near 190℃,which is much higher than the Curie point (126℃) of the crystal.We propose that this peak of the crystals poled by field-cooling above the Curie point is ascribed to the order-disorder transition of the dipoles in polar nano-regions formed at the Burns temperature.
