核壳结构纳米带的磁性研究
发布时间：2018-12-16 11:49
【摘要】：纳米带由于其特有的物理性质和化学性质而受到了极大的关注。而且在磁学、电子学、传感器、储能、生物医学等诸多领域都存在着很大的发展潜力。因此在理论上研究纳米带的磁化特性具有非常重要意义。本文利用相关有效场理论建立微观理论模型,在交换作用、磁晶各向异性等参数的共同作用下,详细的研究了各个相关物理参数对核壳结构四方格子纳米带及类石墨烯纳米带的磁化特性的影响。核壳结构四方格子纳米带的磁矩曲线不仅出现了奈尔理论所预言的Q、P、N三种类型的曲线,而且我们还发现了新的曲线类型,即系统总的平均磁矩曲线上出现了两个补偿点。磁化率具有二次相变的特点,在相变点处表现出奇异现象。由于系统中各物理参数之间相互竞争,导致系统的磁滞回线出现了多环现象。系统在较低的温度下磁矩曲线会出现阶梯的形状,阶梯数量会随着交换作用的增加而逐渐减少,对阶梯效应起到了削弱的效果,在系统中各个物理参数的共同作用下,内核子格子的阶梯和外壳子格子的阶梯会随着外加磁场的不断增加而出现了反转现象。核壳结构类石墨烯纳米带的磁矩曲线在温度比较低的时候会首先出现一个极大值,之后会随着温度的增加而不断减小最后趋近于零但不等于零,这是由于核壳子格子相关物理参数之间相互竞争的结果。系统的磁化率曲线在截止温度处出现了奇异现象。磁滞回线在系统中各物理参数之间相互竞争的作用下会出现多环现象。系统在较低的温度下随着物理参数的改变而出现了不同的阶梯效应。
[Abstract]:Nanobelts have attracted much attention due to their unique physical and chemical properties. And there is great potential in many fields, such as magnetism, electronics, sensor, energy storage, biomedicine and so on. Therefore, it is of great significance to study the magnetization characteristics of nanobelts theoretically. In this paper, the microcosmic theoretical model is established by using the theory of correlation effective field, under the joint action of exchange action, magnetocrystalline anisotropy and other parameters. The effects of various physical parameters on magnetization properties of square lattice nanoribbons and graphene like nanoribbons with core-shell structure were studied in detail. The magnetic moment curves of square lattice nanobelts with core-shell structures not only show three types of curves, as predicted by Nair theory, but also find new types of curves. That is, there are two compensation points on the total average magnetic moment curve of the system. The magnetic susceptibility is characterized by a quadratic phase transition, which shows a singular phenomenon at the transition point. Because the physical parameters of the system compete with each other, the hysteresis loop of the system appears multi-loop phenomenon. At lower temperature, the magnetic moment curve of the system will appear the shape of the ladder, and the number of steps will gradually decrease with the increase of the exchange action, which weakens the step effect, and under the joint action of various physical parameters in the system, The steps of kernel sublattice and shell sublattice will reverse with the increasing of magnetic field. The magnetic moment curve of graphene like nanoribbons with core-shell structure appears a maximum at lower temperature, and then decreases continuously with the increase of temperature, finally approaching zero but not equal to zero. This is due to the competition between the physical parameters of the core-shell lattice. The magnetic susceptibility curve of the system appears singularities at the cutoff temperature. The hysteresis loop will appear multi-loop phenomenon when the physical parameters of the system compete with each other. The system has different ladder effect with the change of physical parameters at lower temperature.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1
本文编号：2382282
[Abstract]:Nanobelts have attracted much attention due to their unique physical and chemical properties. And there is great potential in many fields, such as magnetism, electronics, sensor, energy storage, biomedicine and so on. Therefore, it is of great significance to study the magnetization characteristics of nanobelts theoretically. In this paper, the microcosmic theoretical model is established by using the theory of correlation effective field, under the joint action of exchange action, magnetocrystalline anisotropy and other parameters. The effects of various physical parameters on magnetization properties of square lattice nanoribbons and graphene like nanoribbons with core-shell structure were studied in detail. The magnetic moment curves of square lattice nanobelts with core-shell structures not only show three types of curves, as predicted by Nair theory, but also find new types of curves. That is, there are two compensation points on the total average magnetic moment curve of the system. The magnetic susceptibility is characterized by a quadratic phase transition, which shows a singular phenomenon at the transition point. Because the physical parameters of the system compete with each other, the hysteresis loop of the system appears multi-loop phenomenon. At lower temperature, the magnetic moment curve of the system will appear the shape of the ladder, and the number of steps will gradually decrease with the increase of the exchange action, which weakens the step effect, and under the joint action of various physical parameters in the system, The steps of kernel sublattice and shell sublattice will reverse with the increasing of magnetic field. The magnetic moment curve of graphene like nanoribbons with core-shell structure appears a maximum at lower temperature, and then decreases continuously with the increase of temperature, finally approaching zero but not equal to zero. This is due to the competition between the physical parameters of the core-shell lattice. The magnetic susceptibility curve of the system appears singularities at the cutoff temperature. The hysteresis loop will appear multi-loop phenomenon when the physical parameters of the system compete with each other. The system has different ladder effect with the change of physical parameters at lower temperature.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1
【参考文献】
相关期刊论文 前2条
1 Razieh Beiranvand;;Electronic and magnetic properties of Cd-doped zigzag AlN nanoribbons from first principles[J];Rare Metals;2016年10期
2 冯丽雅;辛子华;王吴韬;;一维钻石链反铁磁Ising模型磁化的模拟[J];计算物理;2010年04期
，本文编号：2382282
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2382282.html
