scholarly journals Scalable microresonators for room-temperature detection of electron spin resonance from dilute, sub-nanoliter volume solids

2020 ◽  
Vol 6 (44) ◽  
pp. eabb0620
Author(s):  
Nandita Abhyankar ◽  
Amit Agrawal ◽  
Pragya Shrestha ◽  
Russell Maier ◽  
Robert D. McMichael ◽  
...  
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Perovskite Oxide ◽  
Paramagnetic Resonance ◽  
Microwave Resonance ◽  
Temperature Detection ◽  
Spin Resonance ◽  
Low Levels ◽  
Electron Paramagnetic

We report a microresonator platform that allows room temperature detection of electron spins in volumes on the order of 100 pl, and demonstrate its utility to study low levels of dopants in perovskite oxides. We exploit the toroidal moment in a planar anapole, using a single unit of an anapole metamaterial architecture to produce a microwave resonance exhibiting a spatially confined magnetic field hotspot and simultaneously high quality-factor (Q-factor). To demonstrate the broad implementability of this design and its scalability to higher frequencies, we deploy the microresonators in a commercial electron paramagnetic resonance (EPR) spectrometer operating at 10 GHz and a NIST-built EPR spectrometer operating at 35 GHz. We report continuous-wave (CW) EPR spectra for various samples, including a dilute Mn2+-doped perovskite oxide, CaTiO3, and a transition metal complex, CuCl2.2H2O. The anapole microresonator presented here is expected to enable multifrequency EPR characterization of dopants and defects in perovskite oxide microcrystals and other volume-limited materials of technological importance.

Defects and Their Distribution in KH2PO4 Crystals with Embedded TiO2 Nanoparticles

2015 ◽  
Vol 1806 ◽  
pp. 13-18 ◽  
Author(s):  
Valentin Grachev ◽  
Romand Tse ◽  
Ian Vrable ◽  
Igor Pritula ◽  
Olga Bezkrovnaya ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Wave Excitation ◽  
Growth Sector ◽  
Paramagnetic Resonance ◽  
Line Intensities ◽  
Anatase Nanoparticles ◽  
Index Changes ◽  
Electron Paramagnetic ◽  
Kdp Crystals

ABSTRACTResults from the successful growth of high quality KH2PO4 (KDP) crystals with incorporated TiO2 anatase nanoparticles and the characterization of these crystals using several complementary methods are presented. Transmission and scanning electron microscopy have shown that the anatase nanoparticles were captured mainly by the pyramidal growth sector and, to a considerably lesser extent, by the prismatic growth sector. Energy dispersive x-ray analysis confirms that the growth layer stacks contain the TiO2 particles. Significant variation in the imaginary and real parts of the cubic nonlinear optical susceptibilities and refractive index changes at continuous wave excitation were found in prism and pyramid parts of pure KDP and KDP:TiO2 samples. The identified lines of electron paramagnetic resonance belong to four different centers FeA3+, FeB3+, CrR3+ and CrGB3+. From analysis of line intensities it was concluded that the concentration of non-controlled impurities in nominally pure KDP samples is several times larger than in KDP:TiO2, and that the concentration of non-controlled impurities in the prismatic part of the KDP:TiO2 boule is larger than in the pyramidal part.

THE PHYSICAL PROPERTIES OF RuS2 − xSex SINGLE CRYSTALS

1993 ◽  
Vol 07 (05) ◽  
pp. 271-290 ◽  
Author(s):  
SHOEI-SHENG LIN ◽  
JENG-KUANG HUANG ◽  
YING-SHENG HUANG
Keyword(s):  
Electrical Transport ◽  
Room Temperature ◽  
Paramagnetic Species ◽  
Electrical Transport Properties ◽  
Defect Model ◽  
Paramagnetic Resonance ◽  
Point Defect Model ◽  
Long Wavelength ◽  
Electron Paramagnetic

In this review, the preparation and characterization of the pyrite-type compound RuS 2 and RuSe 2, as well as the mixed anion compositions RuS 2 − x Se x, are systematically reported. Unusual temperature dependence in electrical transport properties characterize these compounds. Electrolyte electroreflectance measurements were used to get a better understanding of their band structure. Long-wavelength optical phonons have been studied by Raman scattering measurements at room temperature. The nature of defect in these compounds were studied by electron paramagnetic resonance (EPR) investigation. A chalcogen point defect model was established to account for the spin S = 1/2 paramagnetic species detected by EPR.

Electron Paramagnetic Resonance Study of some Alkyl Substituted Cycloalkenyl Radicals

1971 ◽  
Vol 49 (1) ◽  
pp. 20-27 ◽  
Author(s):  
D. R. Gee ◽  
J. K. S. Wan
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Spin Resonance ◽  
Electron Paramagnetic

Well-resolved electron spin resonance (e.s.r.) spectra are reported and analyzed for the radicals produced when samples of solid adamantane doped with alkyl substituted cycloalkenes are γ-irradiated at room temperature.

scholarly journals SOPHE Computation on Alanine Single Crystal EPR Spectra

2011 ◽  
Vol 1 (1) ◽  
pp. 23
Author(s):  
Frida U Ermawati
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Continuous Wave ◽  
Simulation Software ◽  
Software Suite ◽  
Paramagnetic Resonance ◽  
System A ◽  
X Band ◽  
Band Spectra ◽  
Electron Paramagnetic

Simulation of X-band first-derivative continuous-wave electron paramagnetic resonance (CW-EPR) experimental spectra of g-irradiated ℓ-α-alanine single crystal has been carried out. The aim was to confirm the existence of radical induced by irradiation in the system. A SOPHE computer simulation software suite (v. 1.1.3) was utilized for that purpose. Six different X-band spectra measured from a number of defined crystal orientations to the external magnetic field B were recorded and simulated. The “axial” spectra (refer to the simulated spectra when the external B field was parallel to the crystal axes and that was measured at room temperature) confirm the simultaneous presence of the SAR, R2 and R3 radicals with the appropriate proportions. The “planar” spectra (refer to the simulated spectra when the B field was on the crystal planes), however, do not exactly fit to the experimental spectra. Together with the simulation outcomes, the problems that appear during the work, as well as the solutions proposed to overcome those problems are discussed.

Structural and electron paramagnetic resonance (EPR) characterization of novel vanadium(V/IV) complexes with hydroquinonate-iminodiacetate ligands exhibiting “noninnocent” activity

2012 ◽  
Vol 85 (2) ◽  
pp. 329-342 ◽  
Author(s):  
Chryssoula Drouza ◽  
Marios Stylianou ◽  
Petri Papaphilippou ◽  
Anastasios D. Keramidas
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Continuous Wave ◽  
Semiquinone Radical ◽  
Paramagnetic Resonance ◽  
Amine Nitrogen ◽  
Coordination Environment ◽  
X Ray Crystallography ◽  
X Band ◽  
Electron Paramagnetic

Reaction of KVO3 with 2-[N,N'-(carboxymethyl)aminomethyl]-5-methylhydroquinone (H4mecah) in aqueous solution at pH 8.2 results in the isolation of mononuclear K2[VV(O)2{Hmecah(-3)}]·2H2O complex. On the other hand, reaction with the 2-[N,N'-(carboxymethyl)aminomethyl]-5-tert-butylhydroquinone (H4tbutcah) under the same conditions gives the tetranuclear mixed-valent complex K6[{VVO(μ-O)VIVO}{μ-tbutbicah(-6)}]2·10.5H2O (H6tbutbicah, 2,2'-({2-[bis(carboxymethyl)amino]-3,6-dihydroxy-4-methylbenzyl}azanediyl)diacetic acid). The structures of both complexes were determined by single-crystal X-ray crystallography. The coordination environment of vanadium ions in both complexes is octahedral, with four out of the six positions to be occupied by the two cis carboxylate oxygens, one hydroquinonate oxygen, and one amine nitrogen atoms of the ligands’ tripod binding sites. The importance of the chelate ring strains in the stabilization of the p-semiquinone radical is also discussed. A protonation of the ligated to vanadium(IV) ion hydroquinonate oxygen at low pH was revealed by continuous wave (cw) X-band electron paramagnetic resonance (EPR) and UV–vis spectroscopies.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

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