biostudies-literatureLiu CFFrench National Research AgencyChinese University of Hong Kongnwaa194https://www.ebi.ac.uk/biostudies/studies/S-EPMC8288462biostudies-literatureUnknown8(5)Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors because of their long spin coherence time under ambient conditions. However, their spin resonances are relatively insensitive to non-magnetic parameters such as temperature. A magnetic-nanoparticle-nanodiamond hybrid thermometer, where the temperature change is converted to the magnetic field variation near the Curie temperature, were demonstrated to have enhanced temperature sensitivity ([Formula: see text]) (Wang N, Liu G-Q and Leong W-H <i>et al</i>. <i>Phys Rev X</i> 2018; 8: 011042), but the sensitivity was limited by the large spectral broadening of ensemble spins in nanodiamonds. To overcome this limitation, here we show an improved design of a hybrid nanothermometer using a single NV center in a diamond nanopillar coupled with a single magnetic nanoparticle of copper-nickel alloy, and demonstrate a temperature sensitivity of [Formula: see text]. This hybrid design enables detection of 2 mK temperature changes with temporal resolution of 5 ms. The ultra-sensitive nanothermometer offers a new tool to investigate thermal processes in nanoscale systems.National science reviewUltra-sensitive hybrid diamond nanothermometer.PMC82884623110126A-CUHK404/18Xia KLeong WHLiu RBLiu CFFeng XDenisenko AWrachtrup JLi QFinkler AfalseUltra-sensitive hybrid diamond nanothermometer.Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors because of their long spin coherence time under ambient conditions. However, their spin resonances are relatively insensitive to non-magnetic parameters such as temperature. A magnetic-nanoparticle-nanodiamond hybrid thermometer, where the temperature change is converted to the magnetic field variation near the Curie temperature, were demonstrated to have enhanced temperature sensitivity ([Formula: see text]) (Wang N, Liu G-Q and Leong W-H <i>et al</i>. <i>Phys Rev X</i> 2018; 8: 011042), but the sensitivity was limited by the large spectral broadening of ensemble spins in nanodiamonds. To overcome this limitation, here we show an improved design of a hybrid nanothermometer using a single NV center in a diamond nanopillar coupled with a single magnetic nanoparticle of copper-nickel alloy, and demonstrate a temperature sensitivity of [Formula: see text]. This hybrid design enables detection of 2 mK temperature changes with temporal resolution of 5 ms. The ultra-sensitive nanothermometer offers a new tool to investigate thermal processes in nanoscale systems.2021-01-01T00:00:00Z2021 May2025-04-19T20:40:17.195Z2025-04-19T20:40:17.195ZS-EPMC82884623469163510.1093/nsr/nwaa194