Ferrimagnetism induced by asymmetrical ferromagnetic next-nearest-neighbour exchange interactions in an antiferromagnetic spin-1/2 zigzag chain  

作　　者：王忠龙 傅华华 

机构地区：[1]Science College,China Three Gorges University [2]School of Physics,Huazhong University of Science and Technology

出　　处：《Chinese Physics B》2011年第9期408-414,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant No.1010804034);the Science Foundation of China for Three Gorges University (Grant No.KJ2009B012)

摘　　要：The magnetic properties of an antiferromagnetic bond alternating spin-l/2 zigzag chain with asymmetrical ferro- magnetic next-nearest-neighbour exchange interactions at finite temperature are investigated by using the many-body Green＇s function theory. It is found that the ferrimagnetic ordering does not appear in the symmetrical next-nearest- neighbour coupling case, and takes place only for the asymmetrical next-nearest-neighbour case at finite temperature rather than the ground state. Furthermore, as the asymmetry degree of the next-nearest-neighbour exchange inter- actions increases, the ferrimagnetism becomes more and more dominant. It is shown that the elementary excitation spectra are responsible for the observed magnetic behaviour.The magnetic properties of an antiferromagnetic bond alternating spin-l/2 zigzag chain with asymmetrical ferro- magnetic next-nearest-neighbour exchange interactions at finite temperature are investigated by using the many-body Green＇s function theory. It is found that the ferrimagnetic ordering does not appear in the symmetrical next-nearest- neighbour coupling case, and takes place only for the asymmetrical next-nearest-neighbour case at finite temperature rather than the ground state. Furthermore, as the asymmetry degree of the next-nearest-neighbour exchange inter- actions increases, the ferrimagnetism becomes more and more dominant. It is shown that the elementary excitation spectra are responsible for the observed magnetic behaviour.

关 键 词：FERRIMAGNETISM Green＇s function theory zigzag spin chain 

分 类 号：O482.5[理学—固体物理] TB383[理学—物理]