In situ Raman spectroscopy of cubic boron nitride to 90GPa and 800K

AbstractThe temperature and pressure dependences of the Raman spectrum of the transverse-optical mode of cubic boron nitride were calibrated for applications to a Raman spectroscopy pressure sensor in optical cells to about 800K and 90GPa. A significant deviation from linearity of the pressure dependence is confirmed at pressures above 20GPa. At ambient temperature, dv/dP slopes are 3.41(7) and 2.04(7) cm−1/GPa at 0 and 90GPa, respectively. A polynomial expression is used to fit the pressure–temperature dependence of the Raman line. The pressure dependence does not significantly change with temperature, as determined from experiments conducted up to 800K. At 0GPa, the dv/dP slope is 3.46(7)cm−1/GPa at 800K. At pressures above 90GPa, the Raman spectrum of the transverse-optical mode cannot be observed because of an overlap of the signals of cubic boron nitride and diamond used as the anvils in the high-pressure cell