Specialized diamond materials for NMR applications
Polarizable diamond materials and methods for obtaining nuclear magnetic resonance spectra of samples external to the diamond materials are described. The diamond materials can include 12 C, 13 C, substitutional nitrogen, and nitrogen vacancy defects in a crystalline lattice, wherein the substitutional nitrogen concentration is between 10 ppm and 200 ppm, the nitrogen vacancy concentration is between 10 ppb and 10 ppm, and the 13 C concentration is greater than 1.1% and not more than 25%. Methods for obtaining nuclear magnetic resonance spectra can include optically pumping a diamond material to generate electron spin hyperpolarization in nitrogen vacancy centers, transferring the electron spin hyperpolarization to nuclei of the sample, and generating a nuclear magnetic resonance spectrum by applying a magnetic field to the sample, exciting the sample with a radio frequency pulse, and detecting a nuclear magnetic resonance response from the sample.
1. A polarizable diamond material for transfer of nuclear spin polarization comprising 12 C, 13 C, substitutional nitrogen, and nitrogen vacancy defects in a 13 C, crystalline lattice, the polarizable diamond material comprising a diamond crystallite powder comprising crystallites having a diameter between 500 nm and 100 μm;
wherein a substitutional nitrogen concentration in the polarizable diamond material is between 10 ppm and 100 ppm;
wherein a nitrogen vacancy concentration in the polarizable diamond material is between 10 ppb and 10 ppm; and
wherein a 13 C concentration in the polarizable diamond material is greater than 1.1% and not more than 25%.
2. The polarizable diamond material of claim 1 , wherein the 13 C concentration in the diamond material is between 8% and 12%.
3. The polarizable diamond material of claim 1 , wherein the nitrogen vacancy concentration in the diamond material is between 1 ppm and 10 ppm.
4. A method of obtaining a nuclear magnetic resonance spectrum of a sample, the method comprising:
optically pumping a polarizable diamond material to generate electron spin hyperpolarization in nitrogen vacancies within the polarizable diamond material, wherein the polarizable diamond material comprises 12 C, 13 C, substitutional nitrogen, and nitrogen vacancy defects in a crystalline lattice and has a substitutional nitrogen concentration between 10 ppm and 100 ppm, a nitrogen vacancy concentration between 10 ppb and 10 ppm, and a 13 C concentration greater than 1.1% and not more than 25%, the polarizable diamond material comprising a diamond crystallite powder comprising crystallites having a diameter between 500 nm and 100 μm;
transferring the electron spin hyperpolarization directly or indirectly to nuclei of the sample external to the polarizable diamond material; and
generating a nuclear magnetic resonance spectrum by applying a magnetic field to the sample, exciting the sample with a radio frequency pulse, and detecting a nuclear magnetic resonance response from the sample.
5. The method of claim 4 , wherein the 13 C concentration in the polarizable diamond material is between 8% and 12%.
6. The method of claim 4 , wherein the nitrogen vacancy concentration in the polarizable diamond material is between 1 ppm and 10 ppm.
7. The method of claim 4 , wherein the sample comprises a solid having at least a first face, and wherein transferring the electron spin hyperpolarization to nuclei of the sample comprises placing at least some of the crystallites against the first face of the solid.