鐵電磁系統(tǒng)的耦合機制及磁電性質(zhì)研究.pdf

1、蘇州大學碩士學位論文鐵電磁系統(tǒng)的耦合機制及磁電性質(zhì)研究姓名：仲崇貴申請學位級別：碩士專業(yè)：凝聚態(tài)物理指導教師：蔣青2002.4.1璧皇堡墨竺墮塑盒墊型壟垡皇絲墮塹窒塑莖AbstractTheferroelectromagnets，inwhichferroelectricorderingandmagneticspinorderingcoexistspontaneouslyatlowtemperature，havebeentheobject

2、ofintensivetheoreticalandexperimentalstudiesfromthe6070’SlastcenturyforitsconnectionwiththefindingoutthiskindofmaterialandtheirssomespecialpropertiesofphysicsowntomagnetoelectriccouplingBymagnetoelectriccoupling，theappli

3、cationofanelectricfieldorferroelectricpolarizationcanchangeoneormoreoftheparametersgovemingthemagneticbehaviorofthesystemCorrespondingly，beingpossiblemagnetostrictiveeffectorelectron—phononinteraction，thefluctuationofspi

4、norderingmayleadtoadielectricanomalyandferroelectricrelaxationSowecanpreviewthesenewcharactersofthistypeofmaterialontheaspectofphysicspropertywithstudythemagnetoelectriccouplingbetweentheferroelectricorderingandmagnetico

5、rdering，ie，dielectric(magnetic)propertiesoftheferroelectromagnetsmaybealteredbytheonsetofthemagnetic(electric)trasistionorbytheapplicationofamagnetic(electric)fieldThereexistsmagnetoelectriceffectsintwotypeofmaterial，one

6、ofthemisspin—ordermaterialcalledmagnetoelectricsthatmayexhibitsaninducedlinearmagnetoelectriceffectbyexternalfieldThiseffectisnamedastheelectricallyinducedmagnetoelectriceffect(ME)Eormagneticallyinducedmagnetoelectriceff

7、ect(ME)HAferroelectromagnet，however，differsfromthemagnetoelectricsinthatitshowsspontaneousmagnetoelectriceffectsinadditiontothe(ME)EHeffectsinducedbyexternalfieldsTheyarecausedbythecoexistenceinthecrystalofspontaneousfer

8、roelectricandmagneticmomentsAnanomaliesinthedielectricconstantsandlosstangenthavebeenobservedexperimentallyintheferroelectromagnetneartheantiferromagnetictransitiontemperature，indicativeofacouplingbetweentheferroelec‘ica