${\mathrm{Co}}_2\mathrm{MnGa}$ (CMG), a magnetic Weyl semimetal, exhibits high Curie temperature, ultralow damping, and strong spin-dependent transport properties, favorable for spintronics applications. While its room-temperature magnetization dynamics have been explored, the temperature ($T$) dependence of key dynamic parameters such as damping and exchange stiffness remains underexplored. In this work, we investigate the temperature-dependent magnetization dynamics of sputtered CMG thin films (20, 60, and 80 nm) on MgO substrates. We use broadband ferromagnetic resonance spectroscopy with a magnetic field applied perpendicular to the sample plane to characterize these properties. X-ray diffraction reveals a strain-induced tetragonal distortion originating from the substrate-film lattice mismatch, most pronounced in the 20 nm film. As temperature decreases, the saturation magnetization ($M_s$) deviates from Bloch's law below 170 K, due to a temperature-dependent tetragonal distortion. Furthermore, the effective magnetization $M_{\mathrm{eff}}>M_s$ indicates a net in-plane anisotropy that strengthens with decreasing temperature, while the perpendicular uniaxial anisotropy ($K_{u_{\left[001\right]}}$) also increases, with the 20 nm film exhibiting the highest values across all temperatures. Perpendicular standing spin waves observed in the 60 and 80 nm films enable extraction of the exchange stiffness ($A_{ex}$) and exchange length ($l_{ex}$), both of which increase with decreasing temperature. Furthermore, $A_{ex}$ follows a $T^2$ dependence indicative of a dominant contribution from electron-magnon interactions. Compared to the 80 nm film, the 60 nm film has a larger magnetic domain size as revealed by magnetic force microscopy. All films exhibit ultralow damping at room temperature, with the 80 nm film showing a temperature-independent behavior.

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• Magnetization dynamics
• Spin dynamics
• Symmetry protected topological states
• Thermomagnetic effects
• Ferrimagnets
• Heusler alloy
• Magnetic thin films
• Weyl semimetal