【摘要】 弛豫铁电单晶因其具有优异的压电和热释电性能而成为下一代高性能压电换能器和红外热释电探测器用的多功能材料。利用坩埚下降法生长出了大尺寸、高质量的弛豫铁电单晶PMNT(Pb(Mg1/3Nb2/3)O3-xPbTiO3),以及高居里点PIMNT(xPb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-zPbTiO3)单晶。系统研究了其组分诱导相变、电场诱导相变规律,以及相结构、畴结构对晶体高压电性能的影响。系统表征了PMNT单晶的力学、电学、压电、和热释电性能。系统研究了PMNT单晶及掺杂改性的PMNT单晶的结构和性能。利用弛豫铁电单晶PMNT及其复合材料制作了医用超声换能器,其性能相比于PZT陶瓷制作的换能器有大幅度提高;利用PMNT制作了压电能量收集器,实现了高能量密度的机械振动能量收集;利用Mn掺杂的PMNT单晶制作了热释电红外探测器,其电压响应率Rv(500 K,12.5 Hz,25℃)达到14540 V/W,比探测率D*(500 K,12.5 Hz,25℃)达到1.07×109 cmHz1/2W-1;利用PMNT单晶制作了低噪声、高灵敏度的交变弱磁传感器,探测性能达到1 pT.Hz-1/2。更多还原

【Abstract】 Relaxor-based ferroelectric single crystals as a kind of multifunctional material are widely used in transducers and pyroelectric detectors as their excellent piezoelectric and pyroelectric performances.Mass production of Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMNT) and ternary xPb(In1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-zPbTiO3(PIMNT) single crystals with a Bridgman method was reported.The piezoelectric,pyroelectric and electric-optical performances of PMNT single crystals are much more excellent than traditional ceramics with the composition near morphotropic phase boundaries.Compared with PMNT crystal,PIMNT crystals can be used in a more broad range of device applications due to their high Curie temperature Tc and large coercive fields Ec.The phase transitions and domain structures of PMNT are investigated.Medical ultrasonic transducer is made by PMNT single crystals and the composite materials.the performances of the transducer are higher than that of PZT ceramics.The energy harvesting is manufactured by PMNT to achieve the collection of mechanical energy effectively.Pyroelectric infrared detectors are made base on the Mn doped PMNT single crystals,for which the voltage response rate Rv～14540 V/W(500 K,12.5 Hz,25 ℃)and the specific detectivity D*～1.07×109 cmHz1/2W-1(500 K,12.5 Hz,25 ℃).magneto-dependent sensor based on the ME composite is manufactured,the detection sensitivity reach up to 1 pT·Hz-1/2.更多还原