The Magnetism And Adjustment Of Semiconductors And Various Heterostructures

Magnetic semiconductors(DMS)have great application value in the fabrication of electronic devices.DMS combine the storage function of magnetic materials with the logical processing function of semiconductors.Traditional DMS usually have excellent low-temperature properties,but the actual application requires improving their Curie temperature as high as possible.So it is a important task to improve their room temperature maneuverability.Electric field control of magnetism has profound physics significance in the information storage technology area.More and more researchers are aiming to study more obvious electric-field control of magnetism and searching for novel materials applied in this area.Multiferroic heterostructure and diluted magnetic semiconductors are always important materials in the area of electric-field control of magnetism.Since Ohno H,etc.[101]observed the influence of electric field on the magnetism of(InMn)As in 2000,it has been study on the diluted magnetic semiconductors for decades already.Under the background of development of science and technology requirements,my academic dissertation mainly does the research about a few kinds of DMS and materials who has the possibility of achieving electric field control of magnetism.The main problems need to be solved are:1.To prepare multiferroic heterostructures successfully and to adjust their magnetism by electric field.2.To prepare diluted magnetic semiconductors successfully first and then study the influence of electric field to their magnetism,and explore the possibility of electric-field control of DMS's magnetism.The introduction of' my academic dissertation mainly introduces the research developments of diluted magnetic semiconductors(DMS),especially the GaAs-based magnetic semiconductors,the InSb-based magnetic semiconductors and the electric-field control of their magnetism.The research development of electric field control of multiferroic heterostructures' multiferroic heterostructures is also introduced.Next a few film samples' preparation technologies and the method of sample measurement and characterization is introduced.The main experimental work of my academic dissertation is as follows:In the part of multiferroic heterostructures,we prepare the[FeCo/Ag]5nano magnetic multilayer films on the PMN-PT ferroelectric substate by magnetron sputtering method.Thus we combine the ferroelectric material with the ferromagnetic material and prepare[FeCo/Ag]5/PMN-PT multiferroic heterostructures to study the magnetoelectric coupling effect of the system.We study the influcen of electric filed to the heterostructure's magnetism by applying electric field to the system.It was observed during the experiment,the applying of electric field can lead to obvious change in[FeCo/Ag]5/PMN-PT system's magnetism and we can adjust the system's magnetism by adjusting the voltage.Next in the part of diluted magnetic semiconductors(DMS)research,I mainly introduces the experiments on GaAs based DMS and InSb based DMS.In the study of GaAs-based diluted magnetic semiconductor,1.Several groups of GaAs bulk crystals were injected with different doses of Cr element and different doses of Ti element separately by ion implantation method.It was observed that the GaAs bulks exhibit different extents of magnetism at room temperature after the ion implantation.The magnetism changes along with the dose changes.It was found that the dose gets bigger,the sample's magnetism shows stronger.Then we characterize the sample structures.It can be said that we get the GaAs-based diluted magnetic semiconductors at room temperature successfully from the experimental phenomena.2.We did fast and low temperature annealing to the ion-implanted samples GaCrAs and GaTiAs.Then we study the influence of annealing precessing to the magnetism of the samples.We find that low-temperature fast annealing will weaken the magnetism of the samples.In the study of InSb-based diluted magnetic semiconductor,1.Several groups of InSb bulk crystals were injected with different doses of Cr element and different doses of Ti element separately by ion implantation method.It was observed that the InSb bulks exhibit different extents of magnetism at room temperature after the ion implantation.The magnetism changes along with the dose changes.It was found that the dose gets bigger,the sample's magnetism shows stronger.Then we characterize the sample structures.It can be said that we get the InSb-based diluted magnetic semiconductors at room temperature successfully from the experimental phenomena.2.We did fast and low temperature annealing to the ion-implanted samples InCrSb and InTiSb.Then we study the influence of annealing precessing to the magnetism of the samples.We find that low-temperature fast annealing will weaken the magnetism of the samples.