| One-dimensional nanomaterials with unique optical, electrical, magnetic properties, is an ideal energy transfer material which can transfer their electrons, photons, phonons and other particles, and promote its use in cutting-edge technology. In recent years, synthetic methods and preparation techniques of one-dimensional nanomaterials have been rapidly developed. Among them, one-dimensional nanomaterials in information, energy, environment, as well as military fields have had a profound impact. As device miniaturization, to explore the interconnection between future nanoelectronics is an inevitable trend. In addition, the morphology evolution of the one-dimensional structure for understanding the mechanisms and kinetics of crystal growth areas are considered to be ideal for the study. Therefore, studies of one-dimensional nanomaterials which can be applied to the nanotechnology field have very important theoretical value and practical significance.Transition metal oxide compounds are oxygen group elements O, S, Se, Te, etc., compounds forming with various transition metal, which is a very important class of materials in the field of new functional materials and has a very important position. Due to the excellent properties of transition metal chalcogenide nanomaterials in magnetics, electronics and optics, etc., the preparation in the field of electronic nanodevices, lithium ion battery electrode materials, photovoltaic conversion, photocatalysis and sensors have a wide range of application prospects. As deeper understanding and further study of the transition metal chalcogenide materials, people will continue to push the development and use of nanomaterials, consequently to promote more rapid development of human society.In this paper, two typical transition metal oxide compounds were selected, ie monoclinic silver telluride(Ag2Te) and black manganese chrome doped manganese tetroxide(Mn3-xCrxO4) for the study, using hydrothermal and chemical vapor deposition method, through rational design of experiments reaction system, optimizing the experimental reaction conditions, the controllable size and morphology of prepared Ag2 Te and Mn3-xCrxO4 one-dimensional nanomaterials having good crystallinity have been prepared, and studied their magnetic properties, such as magnetoresistance, ferromagnetic, etc., and by means of a metal ion doped materials to improve the performance. The main content of this paper are consist of two main areas:Firstly, we select silver telluride(Ag2Te) as the main object, using a simple hydrothermal method, by changing the reaction time and the kind of the selected surfactant, thereby to adjust the sample morphologies and sizes. By reducing sodium tellurite(Na2Te O3) mixed solution, we prepared one-dimensional Ag2 Te nanomaterials with controlled morphology and size. The morphology evolution of one-dimensional Ag2 Te nanostructures is mainly appropriately controlled by the different reaction time, to adjust the nucleation and growth process. On the basis of transmission electron microscopy(TEM) and scanning electron microscopy(SEM) conducting the research and analysis of the samples, the systematic study of the growth process in Ag2 Te, and the growth mechanism of these products for a reasonable explanation has been proposed. In addition, we also studied the magnetoresistance behavior of Ag2 Te nanowires. The study found that compared to the bulk and thin film materials, due to the reducing sample sizes, R(T) in nanowires occurs a larger change and is more sensitive to external magnetic fields, which indicates the size of the sample has a certain effect on the magnetoresistance. Meanwhile, we also discussed the reasons for the observed formation of the giant magnetoresistance phenomenon.Secondly, using the chemical vapor deposition method(CVD), we successfully synthesized Cr-doped single-crystal Mn3O4 nanowires. By adjusting the ratio of the starting material, Mn3-xCrxO4 nanowires doped with different concentrations(10%, 15%, 20%) were prepared, and the nanowires carried out a detailed study and analysis. Based on this, we tested the magnetic property of Mn3-xCrxO4 nanowires having different dopant concentrations. Experimental results show that the Cr dopant forming Cr3 + ions substitutes the Mn3O4 of Mn3 +, as well as the oxygen vacancies in the sample increases, resulting in an increase in the effective magnetic moment. Room temperature hysteresis loop tests showed the samples achieving a change from paramagnetic to ferromagnetic. Based on these findings, we propose to the doped Cr3+ and oxygen vacancies common synergies generated the Bound Magnetic Polarons(BMPs) model to explain the phenomenon that the Mn3-xCrxO4 ferromagnetic nanowires increased significantly. |
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