Internally heated diamond-anvil cell technique using a boron-doped diamond as a resistive heater up to 100 GPa and 2400 K

Understanding the physicochemical properties of Earth's mantle minerals requires experiments at pressures and temperatures comparable to those in the mantle, which extends to 136 GPa and about 2500 K. While laser-heated diamond-anvil cells (DACs) routinely reach such conditions, internal resistive heating of electrically insulating samples at high pressures is still challenging. Recent advances in chemical vapor deposition (CVD) enable micron-thick boron-doped diamond (BDD) films, which are mechanically robust and electrically conductive, as heater materials inside DACs. Here, we demonstrate a fully CVD-based internally heated DAC that employs a doughnut-shaped BDD thin-film heater. Using Al2O3 as a test sample, we achieve pressures up to ∼100 GPa and temperatures up to ∼2400 K. This approach provides a non-laser route to stable and uniform high-temperature experiments on insulating materials at deep-mantle pressures.