核殼結(jié)構(gòu)納米帶的磁性研究
發(fā)布時間：2018-12-16 11:49
【摘要】：納米帶由于其特有的物理性質(zhì)和化學性質(zhì)而受到了極大的關(guān)注。而且在磁學、電子學、傳感器、儲能、生物醫(yī)學等諸多領(lǐng)域都存在著很大的發(fā)展?jié)摿�。因此在理論上研究納米帶的磁化特性具有非常重要意義。本文利用相關(guān)有效場理論建立微觀理論模型,在交換作用、磁晶各向異性等參數(shù)的共同作用下,詳細的研究了各個相關(guān)物理參數(shù)對核殼結(jié)構(gòu)四方格子納米帶及類石墨烯納米帶的磁化特性的影響。核殼結(jié)構(gòu)四方格子納米帶的磁矩曲線不僅出現(xiàn)了奈爾理論所預言的Q、P、N三種類型的曲線,而且我們還發(fā)現(xiàn)了新的曲線類型,即系統(tǒng)總的平均磁矩曲線上出現(xiàn)了兩個補償點。磁化率具有二次相變的特點,在相變點處表現(xiàn)出奇異現(xiàn)象。由于系統(tǒng)中各物理參數(shù)之間相互競爭,導致系統(tǒng)的磁滯回線出現(xiàn)了多環(huán)現(xiàn)象。系統(tǒng)在較低的溫度下磁矩曲線會出現(xiàn)階梯的形狀,階梯數(shù)量會隨著交換作用的增加而逐漸減少,對階梯效應起到了削弱的效果,在系統(tǒng)中各個物理參數(shù)的共同作用下,內(nèi)核子格子的階梯和外殼子格子的階梯會隨著外加磁場的不斷增加而出現(xiàn)了反轉(zhuǎn)現(xiàn)象。核殼結(jié)構(gòu)類石墨烯納米帶的磁矩曲線在溫度比較低的時候會首先出現(xiàn)一個極大值,之后會隨著溫度的增加而不斷減小最后趨近于零但不等于零,這是由于核殼子格子相關(guān)物理參數(shù)之間相互競爭的結(jié)果。系統(tǒng)的磁化率曲線在截止溫度處出現(xiàn)了奇異現(xiàn)象。磁滯回線在系統(tǒng)中各物理參數(shù)之間相互競爭的作用下會出現(xiàn)多環(huán)現(xiàn)象。系統(tǒng)在較低的溫度下隨著物理參數(shù)的改變而出現(xiàn)了不同的階梯效應。
[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.
【學位授予單位】：沈陽工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB383.1
本文編號：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.
【學位授予單位】：沈陽工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB383.1
【參考文獻】
相關(guān)期刊論文 前2條
1 Razieh Beiranvand;;Electronic and magnetic properties of Cd-doped zigzag AlN nanoribbons from first principles[J];Rare Metals;2016年10期
2 馮麗雅;辛子華;王吳韜;;一維鉆石鏈反鐵磁Ising模型磁化的模擬[J];計算物理;2010年04期
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