A5082660511- Advanced NMR Techniques and Applications
- NMR spectroscopy and applications
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Material Dynamics and Properties
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Nuclear Physics and Applications
- Ionic liquids properties and applications
- Advancements in Battery Materials
- Particle accelerators and beam dynamics
- Dark Matter and Cosmic Phenomena
- Ion-surface interactions and analysis
- 2D Materials and Applications
- Radiation Detection and Scintillator Technologies
- Topological Materials and Phenomena
- Solid-state spectroscopy and crystallography
- Superconducting Materials and Applications
- Crystallography and Radiation Phenomena
- Magnetic Properties of Alloys
- ZnO doping and properties
- Quantum, superfluid, helium dynamics
- Advanced MRI Techniques and Applications
- Glass properties and applications
- Electron Spin Resonance Studies
TRIUMF
2022-2024
University of British Columbia
2016-2023
Simon Fraser University
2023
University of Victoria
2023
Campbell Collaboration
2022
Vancouver Biotech (Canada)
2018-2020
Botswana Geoscience Institute
2018
Currently, no known material retains its photoinduced metallic conductivity over a long time while also exhibiting repeatable metal-to-insulator recovery. Here, we demonstrate such highly insulator-to-metal transition in yttrium oxyhydride (YOxHy) epitaxial thin films. The temperature (T) dependence of the electrical resistivity (ρ) films transforms from insulating to state (dρ/dT > 0) under ultraviolet laser illumination. YOxHy film recovers original when heated (125 °C) an Ar atmosphere...
A new high field spectrometer has been built to extend the capabilities of $\beta$-detected nuclear magnetic resonance ($\beta$-NMR) facility at TRIUMF. This beamline extension allows $\beta$-NMR spectroscopy be performed with fields up 200 mT parallel a sample's surface (perpendicular ion beam), allowing depth-resolved studies local electromagnetic spin polarized probes much higher applied than previously available in this configuration. The primary motivation and application is allow...
We investigated the depth, temperature, and molecular-weight (MW) dependence of γ-relaxation in polystyrene glasses using implanted 8Li+ β-detected nuclear magnetic resonance. Measurements were performed on thin films with MW ranging from 1.1 to 641 kg/mol. The temperature average 8Li spin-lattice relaxation time (T1avg) was measured near free surface bulk. Spin-lattice is caused by phenyl ring flips, which involve transitions between local minima over free-energy barriers enthalpic entropic...
β-NMR measurements indicate there is enhanced phenyl ring dynamics near the free surface in polystyrene thin films.
Beta-detected nuclear magnetic resonance (β-NMR) measures the beta-decay of probe radioactive nuclei to infer electromagnetic character probe's local environment.Similar muon spin rotation (µSR), this technique allows for unique insight material properties not easily measured by conventional NMR.The bfit package provides a graphical user interface (GUI) and application programming (API) facilitate analysis implanted-ion β-NMR measurements taken at TRIUMF.
NMR spectra of Mg2+ ions in ionic liquids were recorded using a highly sensitive variant spectroscopy known as β-NMR. The β-NMR MgCl2 EMIM-Ac and EMIM-DCA compare favourably with conventional NMR, exhibit linewidths ∼3 ppm, allowing for discrimination species oxygen nitrogen coordination.
We report measurements on the high-temperature ionic and low-temperature electronic properties of three-dimensional topological insulator ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{2}\mathrm{Se}$ using ion-implanted $^{8}\mathrm{Li}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$-detected nuclear magnetic relaxation resonance. With implantation energies in range $5--28\phantom{\rule{0.28em}{0ex}}\mathrm{keV}$, probes penetrate beyond expected surface state, but are still within...
We report $\ensuremath{\beta}$-detected NMR of ion-implanted $^{8}\mathrm{Li}$ in a single crystal and thin film the strongly correlated metal ${\mathrm{LaNiO}}_{3}$. Spin-lattice relaxation measurements reveal two distinct local environments, both metallic as evident from $T$-linear Korringa $1/{T}_{1}$ below $200\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ with slopes comparable to other metals. A small approximately temperature-independent Knight shift...
We report $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{NMR}$ measurements in ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}:\mathrm{Ca}$ and ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}:\mathrm{Mn}$ single crystals using $^{8}\mathrm{Li}^{+}$ implanted to depths on the order of 100 nm. Above $\ensuremath{\sim}200\phantom{\rule{4pt}{0ex}}\mathrm{K}$, spin-lattice relaxation reveals diffusion $^{8}\mathrm{Li}^{+}$, with activation energies $\ensuremath{\sim}0.4\phantom{\rule{4pt}{0ex}}\mathrm{eV}$...
We demonstrate the application of implanted-ion $\beta$-detected NMR as a probe ionic liquid molecular dynamics through measurement $^8$Li spin-lattice relaxation (SLR) and resonance in 1-ethyl-3-methylimidazolium acetate. The motional narrowing resonance, local maxima SLR rate, $1/T_1$, imply sensitivity to sub-nanosecond Li$^+$ solvation dynamics. From an analysis we extract activation energy ${E_A = 74.8 \pm 1.5}$ meV Vogel-Fulcher-Tammann constant ${T_{\mathrm{VFT}} 165.8 0.9}$ K,...
We investigate the near-surface relaxation of freestanding atactic \glsdesc{ps} films with molecular dynamics simulations. As in previous coarse-grained simulations, times for backbone segments and phenyl rings are linked to their bulk via a power law coupling relation. Variation exponent distance from surface is consistent depth-dependent activation barriers. also quantify reduction dynamical heterogeneity at interface which can be interpreted framework cooperative models glassy dynamics.
We report on the stability and magnetic state of ion implanted $^{8}\mathrm{Li}$ in single crystals semiconductor ZnO using $\ensuremath{\beta}$-detected nuclear resonance. At ultradilute concentrations, spectra reveal distinct Li sites from 7.6 to 400 K. Ionized shallow donor interstitial is stable across entire temperature range, confirming its ability self-compensate acceptor character (Zn) substitutional counterpart. Above 300 K, spin-lattice relaxation indicates onset correlated local...
<title>Abstract</title> We report direct measurements of the magnetic field screening at limits Meissner phase for two superconducting Nb samples. The samples are processed with different surface treatments that have been developed radio-frequency cavity applications — a “baseline” treatment and an oxygen-doping (“O-doping” ) treatment. show: 1) length is significantly longer in “O-doping” sample compared to sample; 2) near increases applied field; 3) evolution profile as material...
The neutron electric dipole moment (EDM) is a sensitive probe for currently undiscovered sources of charge-parity symmetry violation. As part the TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration, we are developing spin analyzers ultracold neutrons (UCNs) to be used next-generation experiment measure EDM with unprecedented precision. Spin-state analysis UCNs constitutes an essential measurement sequence. Magnetized iron films as filters crucial experimental components, whose...
The neutron electric dipole moment (EDM) is a sensitive probe for currently undiscovered sources of charge-parity symmetry violation.As part the TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration, we are developing spin analyzers ultracold neutrons (UCNs) to be used next-generation experiment measure EDM with unprecedented precision.Spin-state analysis UCNs constitutes an essential measurement sequence.Magnetized iron films as filters crucial experimental components, whose performance...
We report direct measurements of the magnetic field screening at limits Meissner phase for two superconducting Nb samples. The samples are processed with different surface treatments that have been developed radio-frequency cavity applications -- a "baseline" treatment and an oxygen-doping ("O-doping") treatment. show: 1) length is significantly longer in "O-doping" sample compared to sample; 2) near increases applied field; 3) evolution profile as material transitions from mixed phase; 4)...
Abstract The TUCAN nEDM experiment characterizes the QuSpin Zero-Field Magnetometer (QZFM) to accurately map residual fields within a large magnetically shielded room. magnetometer's intrinsic offset was measured be 3 nT and stable over period of one year. response shown 2 percent linearity in zero-field regime, up peak peak, then follows smooth dispersion curve. Crosstalk effects induced by multisensor operation were determined have small effect, inconsequential with separation above 6 cm....
The TUCAN nEDM experiment characterizes the QuSpin Zero-Field Magnetometer (QZFM) to accurately map residual fields within a large magnetically shielded room. magnetometer's intrinsic offset was measured be 3 nT and stable over period of one year. response shown 2 percent linearity in zero-field regime, up nTpp, then follows smooth dispersion curve. Crosstalk effects induced by multisensor operation were determined have small effect, inconsequential with separation above 6 cm. These results...
Abstract We present high (> 2 T) magnetic field β NMR measurements of 8 Li + implanted in single crystals sapphire, a commonly used backing material for other samples. From the well-resolved quadrupolar splitting, we extract electric gradient (EFG) at site. Comparison with supercell density functional theory calculations EFG allows us to identify octahedral interstitial site as most likely candidate. In contrast zero NQR spectra, where multiple singals are detected, only is evident field....
We report $\ensuremath{\beta}$-detected nuclear magnetic resonance of ultradilute $^{8}\mathrm{Li}^{+}$ implanted in highly oriented pyrolytic graphite (HOPG). The absence motional narrowing and diffusional spin-lattice relaxation implies ${\mathrm{Li}}^{+}$ is not appreciably mobile up to 400 K, sharp contrast the lithiated stage compounds. However, remarkably fast persists down cryogenic temperatures. Ruling out extrinsic paramagnetic impurities intrinsic ferromagnetism, we conclude due...
We report the first nuclear magnetic resonance measurements of an atypical transition metal dichalcogenide, CrSe<sub>2</sub>.
Using ion-implanted $^{8}\mathrm{Li} \ensuremath{\beta}$-detected NMR, we study the evolution of correlated metallic state ${\mathrm{LaNiO}}_{3}$ in a series ${\mathrm{LaNiO}}_{3}/{\mathrm{LaAlO}}_{3}$ superlattices as function bilayer thickness. Spin-lattice relaxation measurements an applied field $6.55\phantom{\rule{0.16em}{0ex}}\mathrm{T}$ reveal two equal amplitude components: one with ($T$ linear) $1/{T}_{1}$ and second more complex $T$ dependence. The character slow relaxing component...
The complexation of MgII with adenosine 5'-triphosphate (ATP) is omnipresent in biochemical energy conversion, but difficult to interrogate directly. Here we use the spin- 1/2 β-emitter 31 Mg study -ATP 1-ethyl-3-methylimidazolium acetate (EMIM-Ac) solutions using β-radiation-detected nuclear magnetic resonance (β-NMR). We demonstrate that (nuclear) spin-polarized Mg, following ion-implantation from an accelerator beamline into EMIM-Ac, binds ATP within its radioactive lifetime before...