The magnetic spin Hall effect (MSHE) may produce the out-of-plane current with $z$-direction polarization $({\mathbit{\ensuremath{\sigma}}}_{\mathbf{z}})$, thus allowing field-free switching of perpendicular magnetization in ferromagnetic films. Here, we fabricate epitaxial $L{1}_{1}\text{\ensuremath{-}}\mathrm{CoPt}/D{0}_{19}\text{\ensuremath{-}}\mathrm{M}{\mathrm{n}}_{3}\mathrm{Ga}$ bilayers on MgO(111) substrates and characterize their electrical transport properties. In bilayers, observe...

We report on the development of a microwave frequency standard based laser-cooled 171Yb+ ion trap system. The electronics , lasers, and magnetic shields are integrated into single physical package. With over 105 ions stably trapped, system offers high signal-to-noise ratio Ramsey line-shape. In comparison with previous work, instability clock was further improved to 8.5×10-13/τ for averaging times between 10 1000 s. Essential systematic shifts uncertainties also estimated.

We report a high-performance transportable microwave frequency standard scheme based on sympathetically cooled 113Cd+ ions using 40Ca+ as coolant ions. A physical package (1.4 m3) with magnetic shielding (radial coefficient 460 000) has been built. In experiments, more than 105 were to 90 mK in Paul trap and the ion-loss time constant extends 84 hours. Without direct cooling procedures, Dick effect-limited Allan deviation due deadtimes is reduced 1.8×10−14/τ. Under our scheme, uncertainties...

We measured the ground-state hyperfine splitting of trapped 113Cd+ ions to be 15199862855.02799(27) Hz with a fractional uncertainty 1.8×10-14. The were and laser-cooled in linear quadrupole Paul trap. frequency stability was 4.2×10-13/τ, obtained from Ramsey fringes high signal-to-noise ratios taken over measurement time nearly 5 h, which is close short-term limit estimated Dick effect. Our result consistent previously reported values, but precision four times better than best date.

The ion microwave frequency standard is a candidate for the next generation of with potential very wide applications. Dick effect and second-order Doppler shift (SODFS) limit performance standards. introduction sympathetic cooling technology can suppress SODFS improve stability accuracy standard. However, sympathetically cooled has seldom been studied before. This paper reports high-performance in Paul trap. Using laser-cooled ${}^{40}{\mathrm{Ca}}^{+}$ as coolant ions,...

We reported the realization of a 174Yb+–113Cd+ bi-species Coulomb crystal comprising 174Yb+, heavier ion, as coolant and verified potential applying ion with greater mass than clock to sympathetically cooled microwave frequency standard. The two species massive ions stably trapped in Paul trap make up this large two-component crystal. 113Cd+ are center, which reduces considerably RF heating excess micro-motion subjected. Under scheme, uncertainty due second-order Doppler effect is reduced...

The accurate evaluation of the second-order Doppler frequency shift (SODFS) trapped ions in a linear Paul trap has been studied with experiments and molecular dynamics (MD) simulations. motion three contributions, we focus on ion excess micromotion, which is rarely discussed when evaluating SODFS. Based hypothesis that density uniformly distributed radial direction, propose new model to accurately evaluate total SODFS for microwave clocks. effectiveness verified both simulation experiment,...

Regarding trapped-ion microwave-frequency standards, we report on the determination of hyperfine splittings and Land\'{e} $g_J$ factors $^{111,113}$Cd$^+$. The $5p~^2P_{3/2}$ state $^{111,113}$Cd$^+$ ions were measured using laser-induced fluorescence spectroscopy. Cd$^+$ confined in a linear Paul trap sympathetically cooled by Ca$^+$ ions. Furthermore, $5s~^2S_{1/2}$ $5p~^2P_{1/2,3/2}$ levels calculated with greater accuracy multiconfiguration Dirac--Hartree--Fock scheme. calculation values...

It is intriguing to manipulate light in different ways depending on its properties. This allows a passive device function with versatility without the need for active tuning. In other words, itself can be used as an optical control knob. Multiplexable devices hold immense promise ultrathin integrated processors, capable of manipulating multiple parameters light. this study, inverse design methods are employed optimize wavelength-multiplexed and polarization-multiplexed meta-devices imaging...

Molecular dynamics simulation of a sympathetically-cooled 113 Cd + ion crystal system is achieved. Moreover, the relationship between ions’ axial temperature and different electric parameters, including radio frequency voltage end-cap depicted. Under stable trapping condition, optimum voltage, corresponding to minimum highest cooling efficiency, obtained. The positively correlated with voltage. also confirmed by microwave clock. pseudo-potential model used illustrate influence mechanism. A...

A microwave ion clock based on <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sup> Cd xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ions at Tsinghua University has been carried out for eleven years. To improve the performance of with lower second-order Doppler frequency shift and suppressed Dick effect, a high-performance scheme sympathetically cooling molecular dynamics simulation is reported.

A microwave frequency standard based on ¹¹³Cd^&#x002B; ions at Tsinghua University has been carried out for twelve years. To overcome the limitations of Dick effect and second-order Doppler shift (SODFS), we propose to use heavy ¹⁷⁴Yb^&#x002B; as coolant sympathetically cool large cloud, which is expected further improve performance cadmium-ion standard. This paper reports our recent experimental simulation progress towards

A microwave frequency standard based on laser-cooled ¹⁷¹Yb^&#x002B; ions at Tsinghua University has been investigated. More than 10⁵ were stably trapped for over 40 hours. The ground-state hyperfine splitting of was determined to be 12642812118.4672(8) Hz with a fractional uncertainty 6.33&#x00D7;10^&#x2212;14. Our work is in continuous line that other scholars.

We reported the realization of a $^{174}\mathrm{Yb}^+$-$^{113}\mathrm{Cd}^+$ bi-species Coulomb crystal comprising $^{174}\mathrm{Yb}^+$ ions as coolant and verified its potential for application $^{113}\mathrm{Cd}^+$ microwave frequency standard employing sympathetic cooling.The two species massive stably trapped in Paul trap make up this large two-component crystal. The are center, which reduces considerably RF heating excess micromotion to subjected. Under scheme, uncertainty due...

We report precise measurement of the hyperfine splitting and calculation Zeeman coefficients $^{171}$Yb$^+$ ground state. The absolute frequency is measured using high-resolution laser-microwave double-resonance spectroscopy at 0.1 mHz level, evaluated more accurate coefficients. These are derived Land\'{e} $g_J$ factors calculated by two atomic-structure methods, multiconfiguration Dirac-Hartree-Fock, multireference configuration interaction. cross-check calculations ensures an accuracy...

We investigate 13 hyperfine structures of transition lines 127I2 near 554 nm, namely, the R(50) 22-0, P(46) P(121) 24-0, P(69) 25-1, R(146) 25-0, R(147) 28-1, P(160) 26-0, P(102) 26-1, R(96) 23-0, R(49) P(45) P(92) and R(72) 25-1 transitions, measure their absolute frequencies with an optical frequency comb. A 369 nm frequency-tripled laser is stabilized by locking harmonic-frequency to 25-0 a15 line via modulation transfer spectroscopy. stability 5E-12 observed over a 1000 s integration...

SummaryThe ion microwave frequency standard is a candidate for the next generation of practical standards, which has very wide application potential. Tsinghua University continuously been working on research and development standards. A demonstration experiment two laser-cooled cadmium clocks with zero dead time shows short-term stability τ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-0.95</sup> averaging. Besides, based ions sympathetically...

We report sympathetic cooling of $^{113}$Cd$^+$ by laser-cooled $^{40}$Ca$^+$ in a linear Paul trap for microwave clocks. Long-term low-temperature confinement ions was achieved. The temperature these measured at $90(10)$ mK, and the corresponding uncertainty arising from second-order Doppler shifts estimated to level $2\times10^{-17}$. Up $4.2\times10^5$ Cd$^+$ were confined trap, time constant be 84 hours. After three hours confinement, there still $10^5$ present, indicating that this...

Monodisperse Tb-doped NaCeF₄nanocrystals were synthesized<italic>via</italic>a hydrothermal method.

The ion microwave frequency standard is a candidate for the next generation of with potential very wide applications. Dick effect and second-order Doppler shift (SODFS) limit performance standards. introduction sympathetic cooling technology can suppress SODFS improve stability accuracy standard. However, sympathetically-cooled has seldom been studied before. This paper reports first in Paul trap. Using laser-cooled ${}^{40}\mathrm{{Ca}}^{+}$ as coolant ions, ${}^{113}\mathrm{{Cd}}^{+}$...