Study On Preparation And Performance Of Some New Antiferromagnetic Materials With Heusler Structure

Magnetic thin film is widely used in magnetic memory,but as the disk storage density is still growing at a rate of about 100%per year,the problem of traditional ferromagnetic thin film memory is also becoming increasingly prominent.Anti-ferromagnetic materials can solve this problem very well.Research on antiferromagnetic spintronic materials and devices has just begun.The predecessors predicted that the four films had antiferromagnetic properties,but failed to prepare film-like and antiferromagnetic V-Ga,Cr-Fe-Si,Cr-Mn-Si alloys.The focus of this article is to prepare four series of antiferromagnetic thin films on a silicon substrate by controlling deposition rate,thickness,temperature,and other parameters.And study the film composition,crystallinity,morphology,magnetic properties and electrical properties.The research results of this paper mainly include the following four aspects:First,V₃Ga film preparation.Based on previous predictions,two different processes were used to prepareβ-W-type V₃Ga series thin films,which were commissioned by foreign laboratories for related calculations.Both experiments and theories show that V₃Ga is an antiferromagnetic semiconductor with a narrow band gap of 0.12-0.16 eV.In addition,our calculations predict and experimentally verify there is a strong perpendicular magnetic anisotropy at the V₃Ga/Fe interface.This is due to the phenomenon of strong hybridization between the V atom d and the d orbital state of the Fe atom at the interface.Second,Cr_3-xFe_x（Mn_x）Si film preparation.Based on previous predictions,two antiferromagnetic films of Cr₂FeSi and CrMn₂Si were prepared.Its magnetic resistance does not change with the magnetic field environment and is relatively stable.The experiment also shows that Cr₂FeSi has special thermal resistance properties,while CrMn₂Si exhibits semiconducting properties and the Neel temperature is higher than room temperature.Third,Mn_3-xNi_xGa film preparation.On the basis of previous predictions,we prepared a large number of Mn-Ni-Ga series alloys,although we failed to obtain the Mn_2.4Ni_0.6Ga sample due to the experimental conditions,we found out the film growth process parameters.We also speculate that the magnetic properties of Mn-Ni-Ga series alloys originate from certain materials,and there exists a certain proportion of antiferromagnetic properties in Mn_3-xNi_xGa（0¹）.Fourth,in the process,some of our samples use alternate evaporation.The use of an alternative evaporation process results in a film with higher precision and better crystallinity.With alternating evaporation,when the thickness of each layer is about 2nm,the surface roughness of the resulting film is better,the surface roughness is better,the composition is more precise.In summary,here we prepared a few of new Heusler structure antiferromagnetic material,confirmed its process,and confirmed the magnetic and electrical properties of the film through various means.These materials all have considerable application prospects,and at the same time provides reference for others to prepare similar samples.