多次反射自旋转移矩效应及其微磁学的研究

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1、万方数据硕士毕业论文AbstractSpintronicshasbeenoneofthehottesttopicsincondensedmatterphysicsduetoitspromisingpotentialapplications．Spin—transfertorque(sTr)effectpredictedbySlonczewskiandBergerin1996andlatelyobservedinexperimentin2000hasbeenconsideredasanothermilestonediscove

2、ryafterGiantMagnetoresistance(GMR)effectinthespintronicsfield．Itprovidesasimplewaythatthemagnetizationorientationofmagnetscouldbecontrolledbyaspin—polarizedcurrentinsteadofthemagneticfields．ThefirstproductbasedontheSTFeffect，namelySTT-MRAM，hasiustcomeoutseveralmon

3、thsago．Inthisthesis，wefocusonthestudiesofthemultiplereflectioneffectinthespin—transfertorquedynamicsandthedomainwalldepinningbehavior．Weanalyticallyformulateanexpressionofspin—transfertorquethatcontainsthemultiplereflectioneffectwithintheinterfacesinboththesimpleH

4、ferromagnet／non—ferromag／ferromagnet’spinvalvestructureandthecomplicatemultilayersthatcontains“in．planeandout—of-planedualspinpolarizers“．Thenthemicromagneticsimulationsareperformedtostudythecurrent—drivenmagnetizationswitchingandmagnetizationosillcationfeatures．I

5、naddition，themechanismofthedomainwalldepinninginplanarmagneticnanowireswithanasymmetricnotchhasbeenclarified．ThemaincontentsofthethesisareasfoIlows：WefirstbrieflyreviewtheGMRandSTTeffectandtheirapplicationsinMARMInChapter1．Then，themicromagneticsimulationmethodbase

6、dontheLandau．Lifishitz—Gilbert(LLG)equationusedinthisthesisisintroducedinChapter2．InChapter3，byusingascatteringmatrixmethod，ananalyticspin—transfertorquemodelthatcontainsthemultiplereflectioneffecthasbeenaddressed．IncomparisionwiththecommonSlonczewskiSTTmodel，micr

7、omagneticsimulationsbasedonthenewmodelshowthatthemultiplereflectionscouldreducethecriticalswitchingcurrent．Inaddition，wefoundthatthespinpolarizationofthetwoferromagneticlayerscouldinfluencethecriticalcurrent．Forthemagnetizationfromparalleltoantiparallelswitching，t

8、hecriticalcurrentcouldincrease(decrease)withtheincreaseofthepolarizationofthefreelayer(pinnedlayer)．However，fortheantiparalleltoparallelswitching，thecri