High Sensitivity Spin Defects in Carbon Implanted Diamond

Abstract The TR12 color center in diamond is a self‐interstitial spin defect capable of room‐temperature atomic‐scale vector magnetometry for detecting magnetic fields of arbitrary orientation and magnitude. Measurements using the TR12 center show that the sensing dynamic range can potentially outperform that of NV centers in diamond. The powerful quantum sensing capabilities of TR12 place it as a strong alternative candidate for quantum sensing in diamond, especially in extreme magnetic fields. However, its sensitivity in existing literature is relatively low in the µT/√Hz range. This work examines the spatial distributions of TR12 centers fabricated by high‐energy carbon irradiation on an E‐grade diamond along the ion irradiation cascade. A detailed study of photoluminescence intensity, optically detected magnetic resonance contrast, and linewidth is conducted. By varying locations along ion cascades of line irradiations with different fluences, the highest sensitivity of 1.2 nT/√Hz is achieved at three orders of magnitude higher than demonstrated in existing literatures. Coherent manipulation of triplet spin states in these ensembles is evident from Rabi oscillation measurements, with decoherence times of ≈0.47 µs at the surface and ≈ 0.42 µs at the end‐of‐range. These findings significantly enhance the potential of TR12 for quantum sensing applications.