Thank you. But, this doesn't have any information about the experimental set up. Could you suggest any article on experimental procedure?

Se reference 17 in recommended article

Synthesis. A mixture of Bi2O3 (99.99%) and Mn2O3 with an amountof-substance ratio of 1:1 was carefully ground in acetone and dried at 420 K for 3 days. The starting mixture was sealed in Au capsules. Then high-pressure cells, consisting of graphite heaters and dense NaCl-ZrO2 parts surrounding the Au capsules and separating the Au capsules from graphite heaters, were assembled. Just before the highpressure treatment, the high-pressure cells were dried at 370 K for 12 h under a vacuum. The synthesis was performed in a belt-type high pressure apparatus at 6 GPa and 1383 K for 60-70 min. After heat treatment, the samples were quenched to rt, and the pressure was slowly released. The resultant samples were black powder. X-ray powder diffraction (XRD) showed that the samples were single phased. Singlephased Mn2O3 was prepared by heating commercial MnO2 (99.99%) in air at 923 K for 24 h. Bi2O3 was dried at 570 K before its use. The formation of the powder and single-phased BiMnO3 samples (actually very small single crystals) can be explained by the fact that we used 6 GPa and the much higher synthesis temperature of 1383 K compared with 3-6 GPa and 723-1323 K reported in the literature

go through this article for Vacuum-assisted synthesis

Thank you for the details Mr. Mirgorod.