Method for measuring pressures in a high pressure cell by monitoring continuous changes in physical properties of GeO

1. A method of measuring pressure in high temperature and high pressure processes comprising the steps of:

providing a material sample;

loading the material sample into a device;

subjecting the device and material sample to a high pressure of up to about 10 GPa and a high temperature of up to about 2000° C. to form the material sample into a solid crystalline solution;

recovering the material sample for analysis; and

measuring the composition of the crystalline solid solution to determine the pressure ex situ, wherein the step of providing a material sample further comprises providing a quantity of SiO 2 powder, providing a quantity of GeO 2 powder, and mixing the SiO 2 and GeO 2 powders to form the material sample.

2. The method of claim 1 , wherein pressure and temperature are held constant for a pre-determined time up to 120 minutes.

3. The method of claim 1 , wherein the SiO 2 powder and the GeO 2 are either crystalline or amorphous.

4. The method of claim 1 , further comprising combining the SiO 2 powder and the GeO 2 powder as a glass prior to high pressure treatment.

5. The method of claim 1 , wherein the SiO 2 powder and the GeO 2 powder mixture is derived from sol-gel techniques by reacting alkoxides of Si and Ge.

6. The method of claim 1 , wherein the step of measuring comprises measuring the amount of Si in the solid crystalline solution by electron microprobe analysis.

7. The method of claim 1 , wherein the step of measuring comprises measuring the amount of Si in the solid crystalline solution by X-ray diffraction, wherein the amount of Si in the GeO 2 powder changes the crystal lattice parameters.

8. The method of claim 1 , wherein the step of measuring comprises measuring the amount of Si in octahedral coordination and tetrahedral coordination in the solid crystalline solution by solid state nuclear magnetic resonance of 29 Si, wherein the Si is present in solid solution with GeO 2 .

9. The method of claim 1 , further comprising the step of using the solid crystalline solution as a pressure gauge.

10. The method of claim 1 , wherein the step of providing a material sample further comprises providing a quantity of TiO 2 to form the material sample.

11. A method of measuring pressure in high temperature and high pressure processes, comprising the steps of:

providing at least a first material compound;

providing at least a second material compound;

mixing the at least first and second compounds to form a material sample;

loading the material sample into a device;

subjecting the device and material sample to a high pressure of up to about 10 GPa and a high temperature of up to about 2000° C. to form the material sample into a solid crystalline solution;

recovering the material sample for analysis; and

measuring the composition of the crystalline solid solution to determine the pressure ex situ, wherein the at least first material compound is SiO 2 powder and the at least second material compound is GeO 2 powder and the step of forming the material sample comprises mixing the SiO 2 and GeO 2 powders to form the material sample.

12. The method of claim 11 , wherein pressure and temperature are held constant for a pre-determined time up to 120 minutes.

13. The method of claim 11 , wherein the SiO 2 powder and the GeO 2 are either crystalline or amorphous.

14. The method of claim 11 , further comprising the step of combining the SiO 2 powder and the GeO 2 powder as a glass prior to high pressure treatment.

15. The method of claim 11 , wherein the SiO 2 powder and the GeO 2 powder mixture is derived from sol-gel techniques by reacting alkoxides of Si and Ge.

16. The method of claim 11 , wherein the step of measuring comprises measuring the amount of Si in the solid crystalline solution by electron microprobe analysis, XRD, or NMR.