Antiferromagnetism of Li2Cu5Si4 O14 with alternating dimers and trimers in chains
Journal
Physical Review B
Journal Volume
95
Journal Issue
17
Date Issued
2017
Author(s)
Abstract
The crystal and spin structure of Li2Cu5Si4O14 [chemical formula Li2Cu5(Si2O7)2] can be dissected into a copper spin chain system of alternating Cu2O2 dimers and Cu3O3 trimers linked with corner-shared oxygen and Si2O7 group in three dimensions (3D). The magnetic susceptibility (χ) and specific heat (CP) measurement results suggest the existence of a magnetic ground state of 3D antiferromagnetic (AF) ordering with TN∼22K. Density functional theory (DFT) calculations have been applied to extract the exchange coupling constants for the ground-state spin structure. The calculated dominant intratrimer AF coupling (J1∼-9meV) and the intradimer ferromagnetic (FM) coupling (J3∼1.8meV) supports that the copper spin-1/2 system evolves from a paramagnetic spin chain composed of alternating spin dimer and trimer to the 3D AF ordered ground state on cooling, and a weak frustration is proposed along the chain direction below TN.
Publisher
American Physical Society
Type
journal article