Magnetic properties of (VO)(2)P2O7: Two-plane structure and spin-phonon interactions - art. no. 134418

Detailed experiments on single-crystal (VO)(2)P2O7 continue to reveal new a nd unexpected features. We show that a model composed of two, independent p lanes of spin chains with frustrated magnetic coupling is consistent with n uclear-magnetic-resonance and inelastic-neutron-scattering measurements. Th e pivotal role of PO4 groups in mediating intrachain exchange interactions explains both the presence of two chain types and their extreme sensitivity to certain lattice vibrations, which results in the strong magnetoelastic coupling observed by light scattering. We compute the respective modificati ons of the spin and phonon dynamics due to this coupling, and illustrate th eir observable consequences on the phonon frequencies, magnon dispersions, static susceptibility, and specific heat.