Electro-mechano-optical detection of nuclear magnetic resonance

Signal reception of nuclear magnetic resonance (NMR) usually relies on electrical amplification of the electromotive force caused by nuclear induction. Here, we report up-conversion of a radio-frequency NMR signal to an optical regime using a high-stress silicon nitride membrane that interfaces the electrical detection circuit and an optical cavity through the electro-mechanical and the opto-mechanical couplings. This enables optical NMR detection without sacrificing the versatility of the traditional nuclear induction approach. While the signal-to-noise ratio is currently limited by the Brownian motion of the membrane as well as additional technical noise, we find it can exceed that of the conventional electrical schemes by increasing the electro-mechanical coupling strength. The electro-mechano-optical NMR detection presented here opens the possibility of mechanical parametric amplification of NMR signals. Moreover, it can potentially be combined with the laser cooling technique applied to nuclear spins.Comment: 20 pages, 10 figure

Activities of FexO in Na2O-Al2O3-SiO2-FexO Homogeneous Liquid Slags at 1673 K

Electrochemical measurements of the solid-oxide galvanic cell of the type Mo/Mo + MoO[2]/ZrO[2] (MgO)/Fe + {Na[2]O-Al[2]O[3]-SiO[2]-FexO} slag/Ag/Fe were conducted at 1673 K in order to obtain the activities of FexO in Na[2]O-Al[2]O[3]-SiO[2]-FexO system. The iso-activity curves for FexO at 1673 K were determined for Na[2]O-(Al[2]O[3] + SiO[2])-FexO pseudo-ternary slags with an Al[2]O[3]/SiO[2] molar ratio of 33/67

Field-induced incommensurate phase in the strong-rung spin ladder with ferromagnetic legs

We report magnetization, specific heat, and NMR measurements of 3-Br-4-F-V [=3-(3-bromo-4-fluorophenyl)-1,5-diphenylverdazyl], a strong-rung S=1/2 Heisenberg spin ladder with ferromagnetic leg interactions. We explain the magnetic and thermodynamic properties based on the strong-rung regime. Furthermore, we find a field-induced successive phase transition in the specific heat and the nuclear spin-lattice relaxation rate 1/T1. 19F-NMR spectra for higher- and lower-temperature phases indicate partial magnetic order and incommensurate long-range order, respectively, evidencing the presence of frustration due to weak interladder couplings.Comment: 12 pages, 3 figure

Electronic structure and exchange interactions of the ladder vanadates CaV2O5 and MgV2O5

We have performed ab-initio calculations of the electronic structure and exchange couplings in the layered vanadates CaV2O5 and MgV2O5. Based on our results we provide a possible explanation of the unusual magnetic properties of these materials, in particular the large difference in the spin gap between CaV2O5 and MgV2O5