NMR study on the competing spin chain Rb2Cu2Mo3O12

8th International Conference on Highly Frustrated Magnetism 2016

Yagi, A.^1 ; Matsui, K.^1 ; Goto, T.^1 ; Hase, M.^2 ; Sasaki, T.^3

Physics Division, Sophia University, Chiyodaku Tokyo, 102-8554, Japan^1

National Institute for Materials Science (NTMS), Tsukuba Tbaraki

305-0047, Japan^2

Institute for Material Science(IMR), Tohoku Univ, Sendai

980-8577, Japan^3

关键词: Antiferromagnetic exchange interactions;    Coherent excitations;    Heisenberg system;    Quasi-one dimensional;    Saturation region;    Spin excitation gap;    Temperature dependence;    Thermal activation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/828/1/012016/pdf
DOI  :  10.1088/1742-6596/828/1/012016

来源: IOP

【 摘 要 】

Quasi-one-dimensional S = 1/2 Heisenberg system Rb2Cu2Mo3O12described by the J1- J2model with the nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic exchange interactions have been investigated by87/85Rb-NMR under extended field range up to 18 T. From the thermal-activation-type temperature dependence of l/T1, opening of the spin excitation gap was confirmed under the low field below 2 T. With increasing the field, the system becomes gapless, and the gap opens again in the high field saturation region, where the field dependence of the gap size showed the coherent excitation of the neighbouring two spins.