Magnetic excitations from the linear Heisenberg antiferromagnetic spin trimer system A 3 Cu 3 (P O 4 ) 4 ( A=Ca , Sr, and Pb)

摘要: Inelastic neutron-scattering experiments were performed on ${A}_{3}{\mathrm{Cu}}_{3}{(\mathrm{P}{\mathrm{O}}_{4})}_{4}$ ($A=\mathrm{Ca}$, Sr, and Pb), which consists of one-dimensional array linear copper spin trimers. It was found that the magnetic excitations are well described by Heisenberg antiferromagnetic trimer model, in main interaction is nearest-neighbor intratrimer weak next-nearest-neighbor intertrimer interactions expected. The coupling constants determined to be 9.45(3), 10.04(3), 9.13(2) meV for with $A=\mathrm{Ca}$, Pb, respectively. other very small.