Nature of the ferromagnetic behavior and possible occurrence of the ferrimagnetic phase transition in genuinely organic molecule-based assemblages with an S=1 and S=1/2 antiferromagnetic alternating spin chain: A Green's function approach

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	Nature of the ferromagnetic behavior and possible occurrence of the ferrimagnetic phase transition in genuinely organic molecule-based assemblages with an S=1 and S=1/2 antiferromagnetic alternating spin chain: A Green's function approach
	H. H. Fu ; K. L. Yao ; Z. L. Liu
刊名	Journal of Physical Chemistry A
	2008
卷号	112 期号:27 页码:6205-6210
关键词	nitrophenyl nitronyl nitroxide simple classical pictures numerical-calculations composite molecules magnetic-properties building-blocks ground-state component model system
ISSN号	1089-5639
中文摘要	The temperature dependence of magnetic susceptibility and sublattice magnetizations were calculated for a Heisenberg Hamiltonian of an S = 1 and S = 1/2 antiferromagnetic alternating spin chain by means of the many-body Green's function theory to show the possible occurrence of a ferrimagnetic phase transition for genuinely organic molecule-based magnets. The S = 1 site in the chain is composed of two S = 1/2 spins coupled by a finite ferromagnetic interaction. From the calculated results, it is found that the sublattice magnetization at low-spin S = 1/2 sites changes its sign from negative to positive with increasing temperature, giving rise to the spin alignments along the chain changing from anti ferromagnetic to ferromagnetic ones, which indicates that there is a magnetic phase transition occurring. Because of the weak intermolecular anti ferromagnetic interactions, the curves of the magnetic susceptibility multiplied by temperature (chi T) against temperature show a round peak at low temperatures, which is well consistent with recent experimental observations, and the ferrimagnetic phase transition could only be detected at an ultralow-temperature region and under very weak,external magnetic fields in practical organic materials. From the analysis of the sublattice magnetizations, it is uncovered that the appearance of the low-temperature peak in the curves of the chi T originates from the ferromagnetic spin alignments for all the spins along the chain, and the intermolecular antiferromagnetic interactions play a pivotal role in ferrimagnetic spin alignments of the magnetic systems. It is also found that the higher spatial symmetry of the intermolecular antiferromagnetic interactions have contributions to stabilize the ferrimagnetic ordering state in the molecule-based magnetic materials.
原文出处	://WOS:000257335000019
公开日期	2012-04-13
内容类型	期刊论文
源URL	[http://210.72.142.130/handle/321006/32759]
专题	金属研究所_中国科学院金属研究所
推荐引用方式 GB/T 7714	H. H. Fu,K. L. Yao,Z. L. Liu. Nature of the ferromagnetic behavior and possible occurrence of the ferrimagnetic phase transition in genuinely organic molecule-based assemblages with an S=1 and S=1/2 antiferromagnetic alternating spin chain: A Green's function approach[J]. Journal of Physical Chemistry A,2008,112(27):6205-6210.
APA	H. H. Fu,K. L. Yao,&Z. L. Liu.(2008).Nature of the ferromagnetic behavior and possible occurrence of the ferrimagnetic phase transition in genuinely organic molecule-based assemblages with an S=1 and S=1/2 antiferromagnetic alternating spin chain: A Green's function approach.Journal of Physical Chemistry A,112(27),6205-6210.
MLA	H. H. Fu,et al."Nature of the ferromagnetic behavior and possible occurrence of the ferrimagnetic phase transition in genuinely organic molecule-based assemblages with an S=1 and S=1/2 antiferromagnetic alternating spin chain: A Green's function approach".Journal of Physical Chemistry A 112.27(2008):6205-6210.