Magnetic criticality-enhanced hybrid nanodiamond-thermometer under ambient conditions

Nitrogen vacancy (NV) centres in diamond are attractive as quantum sensors owing to their superb coherence under ambient conditions. However, the NV centre spin resonances are relatively insensitive to some important parameters such as temperature. Here we design and experimentally demonstrate a hybrid nano-thermometer composed of NV centres and a magnetic nanoparticle (MNP), in which the temperature sensitivity is enhanced by the critical magnetization of the MNP near the ferromagnetic-paramagnetic transition temperature. The temperature susceptibility of the NV center spin resonance reached 14 MHz/K, enhanced from the value without the MNP by two orders of magnitude. The sensitivity of a hybrid nano-thermometer composed of a Cu_{1-x}Ni_{x} MNP and a nanodiamond was measured to be 11 mK/Hz^{1/2} under ambient conditions. With such high-sensitivity, we monitored nanometer-scale temperature variation of 0.3 degree with a time resolution of 60 msec. This hybrid nano-thermometer provides a novel approach to studying a broad range of thermal processes at nanoscales such as nano-plasmonics, sub-cellular heat-stimulated processes, thermodynamics of nanostructures, and thermal remanent magnetization of nanoparticles.Comment: 21 pages, 6 figure

Industrially compatible transfusable iPSC-derived RBCs: Progress, challenges and prospective solutions

10.3390/ijms22189808International Journal of Molecular Sciences2218980

Photochemical Reaction of Cp*Ir(CO)₂ with C₆F₅X (X = CN, F): Formation of Diiridium(II) Complexes

Visible light irradiation of Cp*Ir­(CO)₂ (<b>1</b>) in pentafluorobenzontrile resulted in the formation of the two isomeric diiridium­(II) complexes [Cp*Ir­(μ-CO)­(C₆F₄CN)]₂ (<b>3</b>) and [Cp*Ir­(CO)­(C₆F₄CN)]₂ (<b>4</b>), while the analogous reaction of <b>1</b> in hexafluorobenzene to give [Cp*Ir­(μ-CO)­(C₆F₅)]₂ (<b>3a</b>) required UV irradiation. Complex <b>4</b> isomerizes to <b>3</b> under visible light irradiation. A reaction pathway to <b>4</b> involving aromatic nucleophilic substitution has been proposed on the basis of experimental and computational data. The isomerization of <b>4</b> to <b>3</b> is believed to proceed via a radical species resulting from homolytic fission of the Ir–Ir bond

Photochemical Reaction of Cp*Ir(CO)₂ with C₆F₅X (X = CN, F): Formation of Diiridium(II) Complexes

Visible light irradiation of Cp*Ir­(CO)₂ (<b>1</b>) in pentafluorobenzontrile resulted in the formation of the two isomeric diiridium­(II) complexes [Cp*Ir­(μ-CO)­(C₆F₄CN)]₂ (<b>3</b>) and [Cp*Ir­(CO)­(C₆F₄CN)]₂ (<b>4</b>), while the analogous reaction of <b>1</b> in hexafluorobenzene to give [Cp*Ir­(μ-CO)­(C₆F₅)]₂ (<b>3a</b>) required UV irradiation. Complex <b>4</b> isomerizes to <b>3</b> under visible light irradiation. A reaction pathway to <b>4</b> involving aromatic nucleophilic substitution has been proposed on the basis of experimental and computational data. The isomerization of <b>4</b> to <b>3</b> is believed to proceed via a radical species resulting from homolytic fission of the Ir–Ir bond

Zero-field magnetometry using hyperfine-biased nitrogen-vacancy centers near diamond surfaces

Shallow nitrogen-vacancy (NV) centers in diamond are promising for nanomagnetometry, for they can be placed proximate to targets. To study the intrinsic magnetic properties, zero-field magnetometry is desirable. However, for shallow NV centers under zero field, the strain near diamond surfaces would cause level anticrossing between the spin states, leading to clock transitions whose frequencies are insensitive to magnetic signals. Furthermore, the charge noises from the surfaces would induce extra spin decoherence and hence reduce the magnetic sensitivity. Here, we demonstrate that the relatively strong hyperfine coupling (130 MHz) from a first-shell ^{13}C nuclear spin can provide an effective bias field to an NV center spin so that the clock-transition condition is broken and the charge noises are suppressed. The hyperfine bias enhances the dc magnetic sensitivity by a factor of 22 in our setup. With the charge noises suppressed by the strong hyperfine field, the ac magnetometry under zero field also reaches the limit set by decoherence due to the nuclear spin bath. In addition, the 130 MHz splitting of the NV center spin transitions allows relaxometry of magnetic noises simultaneously at two well-separated frequencies (∼2.870 ± 0.065 GHz), providing (low-resolution) spectral information of high-frequency noises under zero field. The hyperfine-bias-enhanced zero-field magnetometry can be combined with dynamical decoupling to enhance single-molecule magnetic resonance spectroscopy and to improve the frequency resolution in nanoscale magnetic resonance imaging