Preparation And Properties Of CoX(X=Zr,Cr)FeSi Heusler Alloy Thin Films

Heusler alloys materials,which have many advantages such as high spin polarization and tunable electronic structure etc,are widely concerned in the field of spintronics device applications and related theoretical studies.Co-based Heusler alloy is one of the research hotspots.On the basis of theoretical calculation and prediction of quaternary Co-based Heusler alloys,series of CoZrFeSi bulk and thin film materials were prepared by vacuum arc melting and physical vapor deposition technologies.Our results show that the as-studied material systems have excellent magnetic properties.and the main results are as follows:The bulk form of CoZrFeSi shows good crystallinity of heusler structure.A2-type structure is observed before annealing treatment,and partially changes to B2-type structure after annealing.Different annealing and cooling procedures exert great influence on the structural and magnetic properties of samples.The study of the temperature-dependent resistance variation shows great possibility of half-metallic nature of CoZrFeSi at room temperature,which is in accordance with theoretical calculation.In addition,CoZrFeSi has very small coercivity and saturation magnetization,which can significantly reduce the hysteretic energy-loss of the material.Therefore,it has a good application prospect in the field of magnetic materials and spin-electronic devices.The crystallinity of CoZrFeSi multilayer films is poor,and can not be improved via annealing treatment.The insertion of Zr and Si layers weaken the ferromagnetic coupling between Fe/Co and greatly reduces the hysteretic energy-loss of the material.Annealing can effectively improve the magnetoresistance of CoZrFeSi multilayers.Compared with the commercial FeCo thin films,the magnetoresistance of CoZrFeSi multilayers does not decrease obviously at room temperature and high temperature under the premise of greatly reducing the coercive force and net magnetic moment,and has a performance advantage.Therefore,CoZrFeSi multilayer has a good application prospect in magnetic storage materials and spin-electronic devices.The crystallinity of CoCrFeSi multilayer films is obviously affected by annealing temperature,in which A2-type structure is partially observed.The ferromagnetic characteristics are not observed,which indicates the destruction of ferromagnetic coupling between Fe/Co after the insertion of Cr.CoCrFeSi multilayers can,t form uniform single phase and show absence of ferromagnetic properties,which on the contrary reflects the significance of excellent magnetic properties of CoZrFeSi multilayer films.