| In recent years,multifunctional materials have attracted considerable interest due to its multi-physical field coupling effect.The research on magnetoelectric coupling,electro-optical coupling and magneto-optical coupling is a hot issue at home and abroad.It has been proposed that they have been applied to magnetoelectric sensors and display equipment.However,multifunctional materials with multiple coupling behaviors have been seldom studied until now.In order to further develop new multi-functional materials possessing multi-physical coupling among magnetic,electric,and optical properties,In present work,a multifunctional material?1-x?Ba0.955Yb0.025Er0.005TiO3-xCoFe2O4?BTO?Yb/Er?-CFO?,owning superior piezoelectric,photoluminescence and magnetostrictive effects,was prepared via the conventional solid-state ceramic fabrication process.Apart from ferroelectric,piezoelectric,dielectric,photoluminescence and magnetic studies,in-situ magneto-electric,electro-photoluminescence and magneto-photoluminescence coupling effects have been investigated in detail.The main results in this dissertation are as follows:1.Based on the previous research,we combined the piezoelectric and photoluminescence system Yb/Er co-doped BaTiO3?BTO?Yb/Er??with ferromagnetic phase CoFe2O4?CFO?,in order to the realization of the photoluminescence effect,ferroelectric,dielectric,piezoelectric and magnetostrictive properties in a single system.The dielectric,ferroelectric,piezoelectric,ferromagnetic and photoluminescence properties of BTO?Yb/Er?-CFO composite ceramics with different CFO contents were studied.With the increase of BTO?Yb/Er?content,the saturation polarizations increased from 8?C/cm2 to 13?C/cm2,the piezoelectric constants increased from 12 pC/N to 22 pC/N,the saturation magnetizations decreased from14.8 emu/g to 5.5 emu/g,and the photoluminescence emission intensity increased gradually in the BTO?Yb/Er?-CFO ceramics.2.The magnetoelectric,electro-optical and magneto-optical coupling effects of BTO?Yb/Er?-CFO composite ceramics with different CFO contents were studied.It was observed that the magnetoelectric coupling coefficients of BTO?Yb/Er?-CFO ceramics were quite stable and kept in the studied bias magnetic field range.Among them,0.65BTO?Yb/Er?-0.35CFO composite ceramics had the largest magnetoelectric coupling coefficient(?E33=11 mV/Oe?cm),and the in-situ ferroelectric domain switching appeared under the bias magnetic field through piezoresponse force microscopy.In addition,in-situ electric/magnetic fields on BTO?Yb/Er?-CFO ceramics can provide an in-situ and dynamic routine to modulate the photoluminescence intensity.For 0.65BTO?Yb/Er?-0.35CFO ceramics,the reversible electric and magnetic modulation ratio of integral intensity of the green emission under 980 nm laser excitation reached 16%@15 kV/cm and 2%@2 kOe,respectively.These results would provide an alternative way to design new multi-physicals coupling and its devices among magnetic,electric,and optical properties. |
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