We have performed high-frequency ESR measurements on powder and aligned samples of one-dimensional quantum ferrimagnets, A3Cu 3(PO4)4, with A = Sr and Ca. Large shifts of paramagnetic g-values were observed. We explain the observed g-shifts by means of an antiferromagnetic trimer model. Moreover, gradual increases of the linewidth of the ESR spectra are observed, indicating that a short-range correlation between the effective spins on the trimers begins to develop with decreasing temperature below 25 K. Analysis of the ESR signal, taking the local structures around Cu2+ ions into account, indicates quantum nature of A3Cu3(PO4)4 compounds.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)