Clean energy technologies like thermoelectric energy generation provide a solution to ease our dependence on fossil fuels. However, the low efficiency of thermoelectric materials find limited applications. Various approaches like grain boundary scattering, substitutional effects, band structure engineering etc. were incorporated to improve the performance to certain extent, yet the phonon-electron interactions in the materials still exist. One way to decouple these interactions is to employ magnetic materials that generate spin currents in the presence of thermal gradient. This new avenue has the potential to extract additional spin voltage thereby increasing the overall Seebeck coefficient of the material. To study this effect, the current research developed a 1-D spin transport model by combining, non-equilibrium Green’s function approach, spin transport theory and first principle calculations based on density functional theory. Using the first principle methods, the fundamental parameters like band gap, effective mass of conduction band edge, lattice parameter and magnetization in the material can be calculated and used in the 1-D spin transport model. The available experimental data for La:YIG was used for validation. In comparison to the experimental data, the spin transport model yielded an error less than 10%. The model developed in this research can be applied to study the spin transport properties of various semiconducting magnetic materials in the presence of thermal gradient.