Raman spectroscopy of cubic boron nitride under high temperature and pressure conditions: A new optical pressure marker

The pressure dependence of Raman peaks of cubic boron nitride (cBN) is determined at 100, 200 and 300 degreesC using pressure scales of ruby and gold. At pressures lower than 6 GPa, the pressure dependences of cBN Raman determined with the ruby pressure scale for transverse-optical (TO) and longitudinal-optical modes are 3.45+/-0.02 and 3.36+/-0.02 cm(-1) /GPa at 100 degreesC and 3.43+/-0.02 and 3.44+/-0.07 cm(-1)/GPa at 300 degreesC, respectively. These values are consistent with those in a previous study conducted at room temperature using the ruby pressure scale. Synchrotron x-ray diffraction experiments using a gold pressure marker also yield 3.45+/-0.03 cm(-1) /GPa for TO mode at 200 degreesC in a range of pressure up to 32 GPa. Under the present pressure and temperature conditions, the pressure dependence of Raman peaks of cBN seems to be independent of the temperature conditions. cBN can be used as an optical pressure marker under high temperature conditions. (C) 2004 American Institute of Physics.