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Dayan N, Artzi Y, Jbara M, Cristea D, Blank A. Pulsed Electron-Nuclear Double Resonance in the Fourier Regime. Chemphyschem 2022; 24:e202200624. [PMID: 36464644 DOI: 10.1002/cphc.202200624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/24/2022] [Accepted: 12/01/2022] [Indexed: 12/11/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy provides atomic-level molecular structural information. However, in molecules containing unpaired electron spins, NMR signals are difficult to measure directly. In such cases, data is obtained using the electron-nuclear double resonance (ENDOR) method, where nuclei are detected through their interaction with nearby unpaired electron spins. Unfortunately, electron spins spread the ENDOR signals, which challenges current acquisition techniques, often resulting in low spectral resolution that provides limited structural details. Here, we show that by using miniature microwave resonators to detect a small number of electron spins, integrated with miniature NMR coils, one can excite and detect a wide bandwidth of ENDOR data in a single pulse. This facilitates the measurement of ENDOR spectra with narrow lines spread over a large frequency range at much better spectral resolution than conventional approaches, which helps reveal details of the paramagnetic molecules' chemical structure that were not accessible before.
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Affiliation(s)
- Nir Dayan
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Yaron Artzi
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Moamen Jbara
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - David Cristea
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
| | - Aharon Blank
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
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2
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Abhyankar N, Agrawal A, Campbell J, Maly T, Shrestha P, Szalai V. Recent advances in microresonators and supporting instrumentation for electron paramagnetic resonance spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:101101. [PMID: 36319314 PMCID: PMC9632321 DOI: 10.1063/5.0097853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/13/2022] [Indexed: 06/16/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy characterizes the magnetic properties of paramagnetic materials at the atomic and molecular levels. Resonators are an enabling technology of EPR spectroscopy. Microresonators, which are miniaturized versions of resonators, have advanced inductive-detection EPR spectroscopy of mass-limited samples. Here, we provide our perspective of the benefits and challenges associated with microresonator use for EPR spectroscopy. To begin, we classify the application space for microresonators and present the conceptual foundation for analysis of resonator sensitivity. We summarize previous work and provide insight into the design and fabrication of microresonators as well as detail the requirements and challenges that arise in incorporating microresonators into EPR spectrometer systems. Finally, we provide our perspective on current challenges and prospective fruitful directions.
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Affiliation(s)
| | - Amit Agrawal
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Jason Campbell
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Thorsten Maly
- Bridge12 Technologies, Inc., Natick, Massachusetts 01760, USA
| | | | - Veronika Szalai
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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3
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Tesi L, Bloos D, Hrtoň M, Beneš A, Hentschel M, Kern M, Leavesley A, Hillenbrand R, Křápek V, Šikola T, van Slageren J. Plasmonic Metasurface Resonators to Enhance Terahertz Magnetic Fields for High-Frequency Electron Paramagnetic Resonance. SMALL METHODS 2021; 5:e2100376. [PMID: 34928064 DOI: 10.1002/smtd.202100376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/28/2021] [Indexed: 06/14/2023]
Abstract
Nanoscale magnetic systems play a decisive role in areas ranging from biology to spintronics. Although, in principle, THz electron paramagnetic resonance (EPR) provides high-resolution access to their properties, lack of sensitivity has precluded realizing this potential. To resolve this issue, the principle of plasmonic enhancement of electromagnetic fields that is used in electric dipole spectroscopies with great success is exploited, and a new type of resonators for the enhancement of THz magnetic fields in a microscopic volume is proposed. A resonator composed of an array of diabolo antennas with a back-reflecting mirror is designed and fabricated. Simulations and THz EPR measurements demonstrate a 30-fold signal increase for thin film samples. This enhancement factor increases to a theoretical value of 7500 for samples confined to the active region of the antennas. These findings open the door to the elucidation of fundamental processes in nanoscale samples, including junctions in spintronic devices or biological membranes.
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Affiliation(s)
- Lorenzo Tesi
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, D-70569, Stuttgart, Germany
| | - Dominik Bloos
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, D-70569, Stuttgart, Germany
| | - Martin Hrtoň
- Institute of Physical Engineering and Central European Institute of Technology, Brno University of Technology, Brno, 616 69, Czech Republic
| | - Adam Beneš
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, D-70569, Stuttgart, Germany
| | - Mario Hentschel
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, D-70569, Stuttgart, Germany
| | - Michal Kern
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, D-70569, Stuttgart, Germany
| | | | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
- CIC nanoGune BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia-San Sebastián, 20018, Spain
| | - Vlastimil Křápek
- Institute of Physical Engineering and Central European Institute of Technology, Brno University of Technology, Brno, 616 69, Czech Republic
| | - Tomáš Šikola
- Institute of Physical Engineering and Central European Institute of Technology, Brno University of Technology, Brno, 616 69, Czech Republic
| | - Joris van Slageren
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, D-70569, Stuttgart, Germany
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4
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Abhyankar N, Agrawal A, Shrestha P, Maier R, McMichael RD, Campbell J, Szalai V. Scalable microresonators for room-temperature detection of electron spin resonance from dilute, sub-nanoliter volume solids. SCIENCE ADVANCES 2020; 6:6/44/eabb0620. [PMID: 33115735 PMCID: PMC7608791 DOI: 10.1126/sciadv.abb0620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
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, CuCl22H2O. 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.
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Affiliation(s)
- Nandita Abhyankar
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA.
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Amit Agrawal
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Pragya Shrestha
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Theiss Research, La Jolla, CA 92037, USA
| | - Russell Maier
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Robert D McMichael
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jason Campbell
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Veronika Szalai
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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5
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Shrestha PR, Abhyankar N, Anders MA, Cheung KP, Gougelet R, Ryan JT, Szalai V, Campbell JP. Nonresonant Transmission Line Probe for Sensitive Interferometric Electron Spin Resonance Detection. Anal Chem 2019; 91:11108-11115. [PMID: 31380627 PMCID: PMC11090209 DOI: 10.1021/acs.analchem.9b01730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron spin resonance (ESR) spectroscopy measures paramagnetic free radicals, or electron spins, in a variety of biological, chemical, and physical systems. Detection of diverse paramagnetic species is important in applications ranging from quantum computation to biomedical research. Countless efforts have been made to improve the sensitivity of ESR detection. However, the improvement comes at the cost of experimental accessibility. Thus, most ESR spectrometers are limited to specific sample geometries and compositions. Here, we present a nonresonant transmission line ESR probe (microstrip geometry) that effectively couples high frequency microwave magnetic field into a wide range of sample geometries and compositions. The nonresonant transmission line probe maintains detection sensitivity while increasing availability to a wider range of applications. The high frequency magnetic field homogeneity is greatly increased by positioning the sample between the microstrip signal line and the ground plane. Sample interfacing occurs via a universal sample holder which is compatible with both solid and liquid samples. The unavoidable loss in sensitivity due to the nonresonant nature of the transmission line probe (low Q) is recuperated by using a highly sensitive microwave interferometer-based detection circuit. The combination of our sensitive interferometer and nonresonant transmission line provides similar sensitivity to a commercially available ESR spectrometer equipped with a high-Q resonator. The nonresonant probe allows for transmission, reflection, or dual-mode detection (transmission and reflection), where the dual-mode results in a √2 signal enhancement.
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Affiliation(s)
- Pragya R. Shrestha
- Theiss Research, La Jolla, California 92037, United States
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Nandita Abhyankar
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Mark A. Anders
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Kin P. Cheung
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Robert Gougelet
- Global Resonance Technologies LLC, Washington D.C. 20015, United States
| | - Jason T. Ryan
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Veronika Szalai
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Jason P. Campbell
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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6
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McCrory DJ, Anders MA, Ryan JT, Shrestha PR, Cheung KP, Lenahan PM, Campbell JP. Slow- and rapid-scan frequency-swept electrically detected magnetic resonance of MOSFETs with a non-resonant microwave probe within a semiconductor wafer-probing station. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:014708. [PMID: 30709237 PMCID: PMC6503682 DOI: 10.1063/1.5053665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
We report on a novel electron paramagnetic resonance (EPR) technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union, which we refer to as wafer-level EDMR (WL-EDMR), allows EDMR measurements to be performed on an unaltered, fully processed semiconductor wafer. Our measurements replace the conventional EPR microwave cavity or resonator with a very small non-resonant near-field microwave probe. Bipolar amplification effect, spin dependent charge pumping, and spatially resolved EDMR are demonstrated on various planar 4H-silicon carbide metal-oxide-semiconductor field-effect transistor (4H-SiC MOSFET) structures. 4H-SiC is a wide bandgap semiconductor and the leading polytype for high-temperature and high-power MOSFET applications. These measurements are made via both "rapid scan" frequency-swept EDMR and "slow scan" frequency swept EDMR. The elimination of the resonance cavity and incorporation with a wafer probing station greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.
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Affiliation(s)
- Duane J. McCrory
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
- Engineering Science and Mechanics, Pennsylvania State University, 101 EES Building, University Park, Pennsylvania 16801, USA
| | - Mark A. Anders
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
- Engineering Science and Mechanics, Pennsylvania State University, 101 EES Building, University Park, Pennsylvania 16801, USA
| | - Jason T. Ryan
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
| | - Pragya R. Shrestha
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
- Theiss Research, La Jolla, California 92037, USA
| | - Kin P. Cheung
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
| | - Patrick M. Lenahan
- Engineering Science and Mechanics, Pennsylvania State University, 101 EES Building, University Park, Pennsylvania 16801, USA
| | - Jason P. Campbell
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, MS 8120, Gaithersburg, Maryland 20899, USA
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7
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Matsumoto N, Itoh N. Measuring Number of Free Radicals and Evaluating the Purity of Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium [DPPH] Reagents by Effective Magnetic Moment Method. ANAL SCI 2018; 34:965-971. [PMID: 30101893 DOI: 10.2116/analsci.18p120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium [DPPH] is widely used as a standard for measuring the number of free radicals. Here, we evaluated the number of free radicals of "DPPH" reagents from three manufacturers by effective magnetic moment method. Interestingly, the reagents from different manufacturers had varying temperature dependencies for both magnetic moment and g-value at low temperatures. As a result, the maximum relative difference among the three reagents on the number of free radicals per unit mass was 20%. Carbon hydrogen nitrogen (CHN) analyses, high-resolution EPR measurements, FT-IR measurement, and NMR measurement confirmed that a major component of only one among the three reagents was "pure" DPPH. The evaluated purity based on free radical content was 0.998 kg kg-1 with expanded uncertainty of 0.036 kg kg-1. The other two reagents were found to be contaminated by several % of benzene in the DPPH crystal structure.
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Affiliation(s)
- Nobuhiro Matsumoto
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)
| | - Nobuyasu Itoh
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)
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8
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Zgadzai O, Twig Y, Wolfson H, Ahmad R, Kuppusamy P, Blank A. Electron-Spin-Resonance Dipstick. Anal Chem 2018; 90:7830-7836. [PMID: 29856211 DOI: 10.1021/acs.analchem.8b00917] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron spin resonance (ESR) is a powerful analytical technique used for the detection, quantification, and characterization of paramagnetic species ranging from stable organic free radicals and defects in crystals to gaseous oxygen. Traditionally, ESR requires the use of complex instrumentation, including a large magnet and a microwave resonator in which the sample is placed. Here, we present an alternative to the existing approach by inverting the typical measurement topology, namely placing the ESR magnet and resonator inside the sample rather than the other way around. This new development relies on a novel self-contained ESR sensor with a diameter of just 2 mm and length of 3.6 mm, which includes both a small permanent magnet assembly and a tiny (∼1 mm in size) resonator for spin excitation and detection at a frequency of ∼2.6 GHz. The spin sensitivity of the sensor has been measured to be ∼1011 spins/√Hz, and its concentration sensitivity is ∼0.1 mM, using reference samples with a measured volume of just ∼10 nL. Our new approach can be applied for monitoring the partial pressure of oxygen in vitro and in vivo through its paramagnetic interaction with another stable radical, as well as for simple online quantitative inspection of free radicals generated in reaction vessels and electrochemical cells via chemical processes.
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Affiliation(s)
- Oleg Zgadzai
- Schulich Faculty of Chemistry , Technion - Israel Institute of Technology , Haifa 3200008 , Israel
| | - Ygal Twig
- Schulich Faculty of Chemistry , Technion - Israel Institute of Technology , Haifa 3200008 , Israel
| | - Helen Wolfson
- Schulich Faculty of Chemistry , Technion - Israel Institute of Technology , Haifa 3200008 , Israel
| | - Rizwan Ahmad
- Department of Biomedical Engineering , Ohio State University , Columbus , Ohio 43210 , United States
| | - Periannan Kuppusamy
- Departments of Radiology and Medicine, Geisel School of Medicine , Dartmouth College , Lebanon , New Hampshire 03756 , United States
| | - Aharon Blank
- Schulich Faculty of Chemistry , Technion - Israel Institute of Technology , Haifa 3200008 , Israel
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9
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McCrory DJ, Anders MA, Ryan JT, Shrestha PR, Cheung KP, Lenahan PM, Campbell JP. Wafer-Level Electrically Detected Magnetic Resonance: Magnetic Resonance in a Probing Station. IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY : A PUBLICATION OF THE IEEE ELECTRON DEVICES SOCIETY AND THE IEEE RELIABILITY SOCIETY 2018; 18:10.1109/TDMR.2018.2817341. [PMID: 30983909 PMCID: PMC6459617 DOI: 10.1109/tdmr.2018.2817341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report on a novel semiconductor reliability technique that incorporates an electrically detected magnetic resonance (EDMR) spectrometer within a conventional semiconductor wafer probing station. EDMR is an ultrasensitive electron paramagnetic resonance technique with the capability to provide detailed physical and chemical information about reliability limiting defects in semiconductor devices. EDMR measurements have generally required a complex apparatus, not typically found in solid-state electronics laboratories. The union of a semiconductor probing station with EDMR allows powerful analytical measurements to be performed within individual devices at the wafer level. Our novel approach replaces the standard magnetic resonance microwave cavity or resonator with a small non- resonant near field microwave probe. Using this new approach we have demonstrated bipolar amplification effect and spin dependent charge pumping in various SiC based MOSFET structures. Although our studies have been limited to SiC based devices, the approach will be widely applicable to other types of MOSFETs, bipolar junction transistors, and various memory devices. The replacement of the resonance cavity with the very small non- resonant microwave probe greatly simplifies the EDMR detection scheme and allows for the incorporation of this powerful tool with a wafer probing station. We believe this scheme offers great promise for widespread utilization of EDMR in semiconductor reliability laboratories.
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Affiliation(s)
- Duane J McCrory
- Engineering Science and Mechanics Department, Pennsylvania State University, University Park, PA 16802 USA
| | - Mark A Anders
- Engineering Physics Division, NIST, Gaithersburg, MD 20874 USA
| | - Jason T Ryan
- Engineering Physics Division, NIST, Gaithersburg, MD 20874 USA
| | | | - Kin P Cheung
- Engineering Physics Division, NIST, Gaithersburg, MD 20874 USA
| | - Patrick M Lenahan
- Engineering Science and Mechanics Department, Pennsylvania State University, University Park, PA 16802 USA
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10
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Switala LE, Black BE, Mercovich CA, Seshadri A, Hornak JP. An electron paramagnetic resonance mobile universal surface explorer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 285:18-25. [PMID: 29065380 DOI: 10.1016/j.jmr.2017.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/12/2017] [Accepted: 10/13/2017] [Indexed: 06/07/2023]
Abstract
Many samples cannot be studied by electron paramagnetic resonance (EPR) spectroscopy because they are too large to fit into the spectrometer and too precious to be destructively sampled for study. An EPR mobile universal surface explorer (MOUSE), also known as a unilateral EPR spectrometer, was constructed for studying this class of sample. The EPR MOUSE can nondestructively record a low frequency EPR (LFEPR) spectrum of a small region of any size object by placing the MOUSE against the object. The capabilities of the EPR MOUSE are demonstrated on paramagnetic paint pigments on canvas, magnetic ink on paper, and a ceramic candlestick. The mobile nature of the MOUSE will allow the spectrometer to be brought to the sample, thus opening new applications of EPR spectroscopy.
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Affiliation(s)
- Lauren E Switala
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604, United States
| | - Baron E Black
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604, United States
| | - Celia A Mercovich
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604, United States
| | - Anjana Seshadri
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604, United States
| | - Joseph P Hornak
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604, United States.
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11
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Kiss SZ, Rostas AM, Heidinger L, Spengler N, Meissner MV, MacKinnon N, Schleicher E, Weber S, Korvink JG. A microwave resonator integrated on a polymer microfluidic chip. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 270:169-175. [PMID: 27497077 DOI: 10.1016/j.jmr.2016.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/16/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10mm by 10mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7·10(11)spins·Hz(-1/2)G(-1) for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.
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Affiliation(s)
- S Z Kiss
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
| | - A M Rostas
- Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - L Heidinger
- Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - N Spengler
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - M V Meissner
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - N MacKinnon
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - E Schleicher
- Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - S Weber
- Institute of Physical Chemistry (IPC), University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - J G Korvink
- Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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12
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Aloisi G, Dolci D, Carlà M, Mannini M, Piuzzi B, Caneschi A. A capacitive probe for Electron Spin Resonance detection. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 263:116-121. [PMID: 26774649 DOI: 10.1016/j.jmr.2015.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 12/26/2015] [Accepted: 12/29/2015] [Indexed: 06/05/2023]
Abstract
The use of the magnetic field associated with Maxwell displacement current in a capacitor is proposed for the detection of Electron Spin Resonance. A probe based on this concept is realized and successfully tested with CW radio-frequency in the band going from 200MHz to 1GHz with a DPPH sample. A significant increase of Signal to Noise Ratio is observed while increasing the frequency.
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Affiliation(s)
- Giovanni Aloisi
- Department of Chemistry and INSTM Research Unit, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy.
| | - David Dolci
- Department of Chemistry and INSTM Research Unit, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy; Department of Physics, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, FI, Italy
| | - Marcello Carlà
- Department of Physics, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, FI, Italy
| | - Matteo Mannini
- Department of Chemistry and INSTM Research Unit, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy
| | - Barbara Piuzzi
- AllTek Innovation S.r.l., Piazza Divisione Julia 4, 33040 Corno di Rosazzo, UD, Italy
| | - Andrea Caneschi
- Department of Chemistry and INSTM Research Unit, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, FI, Italy
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13
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Lloveras V, Badetti E, Wurst K, Chechik V, Veciana J, Vidal-Gancedo J. Magnetic and Electrochemical Properties of a TEMPO-Substituted Disulfide Diradical in Solution, in the Crystal, and on a Surface. Chemistry 2016; 22:1805-15. [PMID: 26743879 DOI: 10.1002/chem.201503306] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/09/2015] [Indexed: 12/15/2022]
Abstract
A study of the magnetic and electrochemical properties of a TEMPO-substituted disulfide diradical in three different environments was carried out: in solution, in the crystal, and as a self-assembled monolayer (SAM) on an Au(111) substrate, and the relationship between them was explored. In solution, this flexible diradical shows a strong spin-exchange interaction between the two nitroxide functions that depends on the temperature and solvent. Structural, dynamic, and thermodynamic information has been extracted from the EPR spectra of this dinitroxide. The magnetic interactions in the crystal include intra- and intermolecular contributions, which have been studied separately and shown to be antiferromagnetic in both cases. Finally, we demonstrate that both the magnetic and electrochemical properties are preserved upon chemisorption of the diradical on a gold surface. The resulting SAM displayed anisotropic magnetic properties, and angle-resolved EPR spectra of the monocrystal allowed a rough determination of the orientation of the molecules in the SAM.
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Affiliation(s)
- Vega Lloveras
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB s/n, 08193, Cerdanyola del Vallès, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN), Barcelona, Spain), Fax
| | - Elena Badetti
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB s/n, 08193, Cerdanyola del Vallès, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN), Barcelona, Spain), Fax
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Center for Chemistry and Biomedicine, Innrain 80-82, 6020, Innsbruck, Austria
| | - Victor Chechik
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
| | - Jaume Veciana
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB s/n, 08193, Cerdanyola del Vallès, Spain.,CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN), Barcelona, Spain), Fax
| | - José Vidal-Gancedo
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB s/n, 08193, Cerdanyola del Vallès, Spain. .,CIBER de Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN), Barcelona, Spain), Fax.
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Switala LE, Ryan WJ, Hoffman M, Brown W, Hornak JP. Low Frequency EPR and EMR Point Spectroscopy and Imaging of a Surface. Magn Reson Imaging 2015; 34:469-72. [PMID: 26706135 DOI: 10.1016/j.mri.2015.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/12/2015] [Indexed: 11/15/2022]
Abstract
Low frequency electron paramagnetic resonance (LFEPR) spectrometers operating between 100 and 500 MHz typically have large-volume magnets that accommodate large samples. LFEPR spectroscopy with a 2.9 mm diameter surface coil was used to record point spectra and image the spatial distribution of the spin probe 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and electrophotographic toner in printed letters on a flat surface. The location of the surface coil was fixed on the desired location when a spectrum was recorded. The magnetic field of the spectrometer was fixed on the location of the signal and the sample was scanned under the surface coil in parallel trajectories to produce an image of the signal in the letters "LFEPR". We speculate on the utility of this technique to study flat objects such as paintings and illuminated manuscripts with cultural heritage significance.
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Affiliation(s)
- Lauren E Switala
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604
| | - William J Ryan
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604
| | | | - Wyatt Brown
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604
| | - Joseph P Hornak
- Magnetic Resonance Laboratory, Rochester Institute of Technology, Rochester, NY 14623-5604.
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