Evidence of spin–phonon–charge coupling and spin–orbit excitations in quasi-one-dimensional Ising spin chain system <i>α</i> –CoV ₂ O ₆

The quasi-one-dimensional Ising spin chain<i>α</i>-CoV₂O₆exhibits intriguing low-temperature magnetic behavior. We report a comprehensive study of the magnetic and lattice properties of the quasi-one-dimensional Ising spin-chain compound<i>α</i>-CoV₂O₆using x-ray diffraction, DC magnetization, specific heat, Raman spectroscopy, and theoretical charge density calculations. Antiferromagnetic (AFM) long-range order is observed atTN=15 K, with short-range magnetic correlations persisting below 100 K. The Co²⁺ions exhibit an effective spin-1/2 ground state due to crystal-field effects and strong spin-orbit coupling. Temperature-dependent Raman and XRD measurements reveal pronounced spin-phonon and magnetoelastic coupling, with anomalies nearTN and signatures of short-range ordering well above the magnetic transition. These couplings play a crucial role in stabilizing the magnetic plateau and highlight the interplay between spin, lattice, and charge degrees of freedom. Theoretical charge density calculations confirm spin-charge coupling via p-d hybridization, leading to electric dipole formation in the AFM state.