Spin-phonon coupling in ferrimagnet spinel CoMn2O4

Coupling of material properties provides new fundamental insights and possibilities toward multifunctional devices. The spinel structures display strong coupling between different order parameters, as a consequence, exhibiting many fascinating properties like multiferroicity, superconductivity etc. Here, we have investigated structural, magnetic, and vibrational properties of mixed-spinel CoMn2O4, stabilized in distorted tetragonal structure as evidenced from X-ray diffraction measurements. Magnetization measurements reveal two ferrimagnetic phase transitions at 185 K and 90 K. Raman scattering measurements reveal the renormalization of phonon parameters for a few phonon modes at low temperatures, arising from spin-phonon coupling. The obtained value for λS2 is ~ 2 cm-1. The strength of the spin-phonon coupling (λ) is estimated according to the spins involved in corresponding lattice vibrations and discussed.