Fig. 1. Structural representation of the refrigeration system and sample chamber

Fig. 2. SEM images of MgB₂ film at different magnifications

Fig. 3. R-T curve of the MgB₂ film

Fig. 4. Raman spectra of SiC substrate at room temperature and MgB₂ film at different temperatures

Fig. 5. Treatment of Raman spectrum of MgB₂ film at 10 K

Fig. 6. Change of position and FWHM of Raman peak at 620 cm^-1 with temperature