arXiv subjects

G. Yue

Publications and source records attributed to G. Yue.

3 recordsLinked to original sources

arXiv2017

Sensitive spin detection using an on-chip SQUID-waveguide resonator

Precise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a novel setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated from 20~nm Nb thin film, allowing high magnetic field operation with the field applied parallel to the chip. We observe a resonance signal between the first and third excited states of Gd spins $S=7/2$ in a CaWO$_4$ crystal, relevant for state control in multi-level systems.

cond-mat.mes-hall↗

arXiv2017

Forbidden coherent transfer observed between two realizations of quasi-harmonic spin system

The multi-level system $^{55}$Mn$^{2+}$ is used to generate two pseudo-harmonic level systems, as representations of the same electronic sextuplet at different nuclear spin projections. The systems are coupled using a forbidden nuclear transition induced by the crystalline anisotropy. We demonstrate Rabi oscillations between the two representations in conditions similar to two coupled quasi-harmonic quantum oscillators. Rabi oscillations are performed at a detuned pumping frequency which matches energy difference between electro-nuclear states of different oscillators. We measure a coupling stronger than the decoherence rate, to indicate the possibility fast information exchange between the systems.

cond-mat.str-el↗

arXiv2015

Magnetism and a field-cycling induced effect in staircase Kagomé antiferromagnet PbCu$_3$TeO$_7$ revealed by NMR

We report $^{125}$Te and $^{63,65}$Cu nuclear magnetic resonance (NMR) studies on single crystals of staircase Kagomé antiferromagnet PbCu3TeO7 ($T_{N1}\approx$ 36 K). A Curie constant as large as $Θ$~140 K is obtained by a Curie-Weiss fitting of the high-temperature Knight shift. The frustration factor f (= $Θ/T_N $)$\approx$ 4 implies intermediate frustration in this system. From the high-temperature Knight shift data of $^{125}$Te, its hyperfine coupling constant is estimated to be $^{125}A_{hf}$ = -67 kOe/$μ_B$, which suggests a strong interlayer coupling bridging the neighboring Kagomé layers. At $T$= 2 K, we find two types of zero-field NMR signals. One has no dependence on the history of the field treatment, which is consistent with Cu NMR signals from inequivalent Cu sites with different internal hyperfine fields. The other one is only seen after a field-cycling process, which is consistent with domain wall contributions in this frustrated antiferromagnet.

cond-mat.str-el↗