Preparation Process And Magnetic NdFeB / Nd Permanent Magnetic Multilayer Films Can Be Studied

NdFeB magnetic materials appeared in the1980s,because its prominent magneticproperties it was concerned by the world since its apperance. Currently,NdFeB magneticmaterials were widely used in communications,medical,aerospace,automotive and otherhigh-tech industry.In this paper,Mo/Nd/NdFeB/Nd/Mo mutilayers and [NdFeB/Nd]n alternative mutilayerswere prepared by magnetron sputtering.The influence on NdFeB orgnizationalstructure,surface morphology and magnetic properties made by the heat treatmenttemperature,films thinkness,the number of alternative mutilayer films and test temperaturewere studied.The films grain size was determined by the atomic force microscope（AFM）,the phase structrue was analysized by the X-ray powder diffractometer (XRD),thefilm,s cross-section growth condition was observed through the scanning electron microscope(SEM).The magnetic properties were measured on LDJ9600Vibrating SampleMagnetometer(VSM).Mo/Nd/NdFeB/Nd/Mo mutilayers were prepared by magnetron sputtering in FJL560ultrahigh vacuum magnetron sputtering and ion beam equipment.Annealed at differeenttemperature,the influence of temperature on films magnetic properties were studied.It wasfound that the Nd2Fe14B appeared only after annealing at570oC,it shown that570oC is theMo/Nd/NdFeB/Nd/Mo films begining crystalization temperature.There were many Nd2Fe14Bpeak appearance in the film phase structure，the (312),(216) paek are higher compared with(008). From this we can say that Nd2Fe14B hard magnetic phase was got succefully afterannealed and the vertical alignment is not obvious.Prior to630oC with the increasing ofanneanling temperature the films corecivity raised and the squareness became better;After630oC,with the increasing of anneanling temperature the corecivity decreased.This is becausehigher temperature is good for the films crystallinity and also it is favor of Nd atom difussionin Mo/Nd/NdFeB/Nd/Mo films,so there were more Nd can combinewithα-Fe which lead tomore Nd2Fe14B phase made and the corecivity increase,when temperature was too high thegrain coarsen.So the films best annealing temperature is630oC.The best parallel direction andVertical direction coercivity are21.8kOe,15.2kOe and the Magnetic product are19.0MGOe,11.9MGOe respectively.Compared with just one number of NdFeB/Nd,the NdFeB/Nd multilayers can make NdFeB and Nd combinated fully,therefore it can improve films magnetic properties.Keep thetotal thinkness of NdFeB and Nd constant,with the increase of NdFeB/Nd number,theparallel direction and Vertical direction coercivity and Magnetic product both increased firstlyand then decreased and also the parallel value are higher then the Vertical direction,this wasthe films exhibits a plane orientation.When n=8the film magnetic performance were thebest.They were: Hci∥=25.07kOe，（BH）max∥=13.98MGOe；Hci⊥=11.7kOe，（BH）max⊥=5.09MGOe.The temperature stability coefficient of Monolayer films and multilayer films rise withthe temperature falling.