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, such as multiferroicity and superconductivity. Here, we have investigated the structural, magnetic, and vibrational properties of mixed-spinel CoMn₂O₄ stabilized in distorted tetragonal structures as evidenced from x-ray diffraction measurements. Magnetization measurements reveal two ferrimagnetic phase transitions at 185 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 spin-phonon coupling (λ) is estimated according to the spins involved in the corresponding lattice vibrations and discussed.