Correlation between charge transfer and exchange coupling in carbon-based magnetic materials

Several forms of carbon-based magnetic materials, i.e. single radicals, radical dimers, and alternating stacks of radicals and diamagnetic molecules, have been investigated using density-functional theory with dispersion correction and full geometry optimization. Our calculated results demonstrate that the C31H15 (R4) radical has a spin of However, in its [R4]2 dimer structure, the net spin becomes zero due to antiferromagnetic spin-exchange between radicals. To avoid antiferromagnetic spin-exchange of identical face-to-face radicals, eight alternating stacks, R4/D2m/R4 (with m = 3-10), were designed. Our calculated results show that charge transfer (Δn) between R4 radicals and the diamagnetic molecule D2m occurs with a mechanism of spin exchange (J) in stacks. The more electrons that transfer from R4 to D2m, the stronger the ferromagnetic spin-exchange in stacks. In addition, our calculated results show that Δn can be tailored by adjusting the electron affinity (Ea) of D2m. The correlation between Δn, Ea, m, and J is discussed. These results give some hints for the design of new ferromagnetic carbon-based materials.

Title:	Correlation between charge transfer and exchange coupling in carbon-based magnetic materials
Authors:	Nguyen, Anh Tuan Nguyen, Van Thanh Pham, Thi Tuan Anh Do, Viet Thang Nguyen, Huy Sinh Dam, Hieu Chi
Keywords:	Antiferromagnetism Ferromagnetism Dispersion correction Ferromagnetic spin
Issue Date:	2015
Publisher:	American Institute of Physics Inc.
Citation:	Scopus
Abstract:	Several forms of carbon-based magnetic materials, i.e. single radicals, radical dimers, and alternating stacks of radicals and diamagnetic molecules, have been investigated using density-functional theory with dispersion correction and full geometry optimization. Our calculated results demonstrate that the C31H15 (R4) radical has a spin of However, in its [R4]2 dimer structure, the net spin becomes zero due to antiferromagnetic spin-exchange between radicals. To avoid antiferromagnetic spin-exchange of identical face-to-face radicals, eight alternating stacks, R4/D2m/R4 (with m = 3-10), were designed. Our calculated results show that charge transfer (Δn) between R4 radicals and the diamagnetic molecule D2m occurs with a mechanism of spin exchange (J) in stacks. The more electrons that transfer from R4 to D2m, the stronger the ferromagnetic spin-exchange in stacks. In addition, our calculated results show that Δn can be tailored by adjusting the electron affinity (Ea) of D2m. The correlation between Δn, Ea, m, and J is discussed. These results give some hints for the design of new ferromagnetic carbon-based materials.
Description:	AIP Advances, Volume 5, Issue 10, 1 October 2015, Article number 107109
URI:	http://repository.vnu.edu.vn/handle/VNU_123/31044
ISSN:	21583226
Appears in Collections:	Bài báo của ĐHQGHN trong Scopus