1
|
Kalendra V, Turčak J, Usevičius G, Karas H, Hülsmann M, Godt A, Jeschke G, Banys J, Morton JJL, Šimėnas M. Q-band EPR cryoprobe. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 356:107573. [PMID: 37856964 DOI: 10.1016/j.jmr.2023.107573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Following the success of cryogenic EPR signal preamplification at X-band, we present a Q-band EPR cryoprobe compatible with a standard EPR resonator. The probehead is equipped with a cryogenic ultra low-noise microwave amplifier and its protection circuit that are placed close to the sample in the same cryostat. Our cryoprobe maintains the same sample access and tuning which is typical in Q-band EPR, as well as supports high-power pulsed experiments on typical samples. The performance of our setup is benchmarked against that of existing commercial and home-built Q-band spectrometers, using CW EPR and pulsed EPR/ENDOR experiments to reveal a significant sensitivity improvement which reduces the measurement time by a factor of about 40× at 6 K temperature at reduced power levels.
Collapse
Affiliation(s)
- Vidmantas Kalendra
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania; Amplify My Probe Ltd., London NW1 1NJ, UK
| | - Justinas Turčak
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Gediminas Usevičius
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Hugo Karas
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Miriam Hülsmann
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Jūras Banys
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - John J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Electronic & Electrical Engineering, University College London, London WC1E 7JE, UK
| | - Mantas Šimėnas
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania.
| |
Collapse
|
2
|
Kalendra V, Turčak J, Banys J, Morton JJL, Šimėnas M. X- and Q-band EPR with cryogenic amplifiers independent of sample temperature. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 346:107356. [PMID: 36516664 DOI: 10.1016/j.jmr.2022.107356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/03/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Inspired by the success of NMR cryoprobes, we recently reported a leap in X-band EPR sensitivity by equipping an ordinary EPR probehead with a cryogenic low-noise microwave amplifier placed closed to the sample in the same cryostat [Šimėnas et al. J. Magn. Reson.322, 106876 (2021)]. Here, we explore, theoretically and experimentally, a more general approach, where the amplifier temperature is independent of the sample temperature. This approach brings a number of important advantages, enabling sensitivity improvement irrespective of sample temperature, as well as making it more practical to combine with ENDOR and Q-band resonators, where space in the sample cryostat is often limited. Our experimental realisation places the cryogenic preamplifier within an external closed-cycle cryostat, and we show CW and pulsed EPR and ENDOR sensitivity improvements at both X- and Q-bands with negligible dependence on sample temperature. The cryoprobe delivers signal-to-noise ratio enhancements that reduce the equivalent pulsed EPR measurement time by 16× at X-band and close to 5× at Q-band. Using the theoretical framework we discuss further improvements of this approach which could be used to achieve even greater sensitivity.
Collapse
Affiliation(s)
- Vidmantas Kalendra
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania; Amplify My Probe Ltd., London NW1 1NJ, UK
| | - Justinas Turčak
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Jūras Banys
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - John J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Dept. of Electronic & Electrical Engineering, University College London, London WC1E 7JE, UK
| | - Mantas Šimėnas
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Teucher M, Sidabras JW, Schnegg A. Milliwatt three- and four-pulse double electron electron resonance for protein structure determination. Phys Chem Chem Phys 2022; 24:12528-12540. [PMID: 35579184 DOI: 10.1039/d1cp05508a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) experiments for protein structure determination using double electron-electron resonance (DEER) spectroscopy rely on high-power microwave amplifiers (>300 W) to create the short pulse lengths needed to excite a sizable portion of the spectrum. The recently introduced self-resonant microhelix combines a high B1 conversion efficiency with an intrinsically large bandwidth (low Q-value) and a high absolute sensitivity. We report dead times in 3-pulse DEER experiments as low as 14 ± 2 ns achieved using less than 1 W of power at X-band (nominally 9.5 GHz) for experiments on a molecular ruler and a T4 lysozyme sample for concentrations down to 100 μM. These low-power experiments were performed using an active volume 120 times smaller than that of a standard pulse EPR resonator, while only a 11-fold decrease in the signal-to-noise ratio was observed. Small build sizes, as realized with the microhelix, give access to volume-limited samples, while shorter dead times allow the investigation of fast relaxing spin species. With the significantly reduced dead times, the 3-pulse DEER experiment can be revisited. Here, we show experimentally that 3-pulse DEER offers superior sensitivity over 4-pulse DEER. We assert that the microhelix paves the road for low-cost benchtop X-band pulse EPR spectrometers by eliminating the need for high-power amplifiers, accelerating the adoption of pulse EPR to a broader community.
Collapse
Affiliation(s)
- Markus Teucher
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
| | - Jason W Sidabras
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
| | - Alexander Schnegg
- EPR Research Group, Max Planck Institute for Chemical Energy Conversion, Stift-straße 34-36, Mülheim an der Ruhr, 45470, Germany.
| |
Collapse
|
5
|
Šimėnas M, O'Sullivan J, Zollitsch CW, Kennedy O, Seif-Eddine M, Ritsch I, Hülsmann M, Qi M, Godt A, Roessler MM, Jeschke G, Morton JJL. A sensitivity leap for X-band EPR using a probehead with a cryogenic preamplifier. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 322:106876. [PMID: 33264732 DOI: 10.1016/j.jmr.2020.106876] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 06/12/2023]
Abstract
Inspired by the considerable success of cryogenically cooled NMR cryoprobes, we present an upgraded X-band EPR probehead, equipped with a cryogenic low-noise preamplifier. Our setup suppresses source noise, can handle the high microwave powers typical in X-band pulsed EPR, and is compatible with the convenient resonator coupling and sample access found on commercially available spectrometers. Our approach allows standard pulsed and continuous-wave EPR experiments to be performed at X-band frequency with significantly increased sensitivity compared to the unmodified setup. The probehead demonstrates a voltage signal-to-noise ratio (SNR) enhancement by a factor close to 8× at a temperature of 6 K, and remains close to 2× at room temperature. By further suppressing room-temperature noise at the expense of reduced microwave power (and thus minimum π-pulse length), the factor of SNR improvement approaches 15 at 6 K, corresponding to an impressive 200-fold reduction in EPR measurement time. We reveal the full potential of this probehead by demonstrating such SNR improvements using a suite of typical hyperfine and dipolar spectroscopy experiments on exemplary samples.
Collapse
Affiliation(s)
- Mantas Šimėnas
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
| | - James O'Sullivan
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
| | | | - Oscar Kennedy
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
| | - Maryam Seif-Eddine
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London W12 0BZ, UK
| | - Irina Ritsch
- ETH Zürich, Department of Physical Chemistry, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Miriam Hülsmann
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, Bielefeld 33615, Germany
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, Bielefeld 33615, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, Bielefeld 33615, Germany
| | - Maxie M Roessler
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London W12 0BZ, UK
| | - Gunnar Jeschke
- ETH Zürich, Department of Physical Chemistry, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - John J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Electronic & Electrical Engineering, UCL, London WC1E 7JE, UK.
| |
Collapse
|
6
|
Sidabras JW, Duan J, Winkler M, Happe T, Hussein R, Zouni A, Suter D, Schnegg A, Lubitz W, Reijerse EJ. Extending electron paramagnetic resonance to nanoliter volume protein single crystals using a self-resonant microhelix. SCIENCE ADVANCES 2019; 5:eaay1394. [PMID: 31620561 PMCID: PMC6777973 DOI: 10.1126/sciadv.aay1394] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/06/2019] [Indexed: 05/26/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy on protein single crystals is the ultimate method for determining the electronic structure of paramagnetic intermediates at the active site of an enzyme and relating the magnetic tensor to a molecular structure. However, crystals of dimensions typical for protein crystallography (0.05 to 0.3mm) provide insufficient signal intensity. In this work, we present a microwave self-resonant microhelix for nanoliter samples that can be implemented in a commercial X-band (9.5 GHz) EPR spectrometer. The self-resonant microhelix provides a measured signal-to-noise improvement up to a factor of 28 with respect to commercial EPR resonators. This work opens up the possibility to use advanced EPR techniques for studying protein single crystals of dimensions typical for x-ray crystallography. The technique is demonstrated by EPR experiments on single crystal [FeFe]-hydrogenase (Clostridium pasteurianum; CpI) with dimensions of 0.3 mm by 0.1 mm by 0.1 mm, yielding a proposed g-tensor orientation of the Hox state.
Collapse
Affiliation(s)
- Jason W. Sidabras
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Jifu Duan
- AG Photobiotechnologie, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Martin Winkler
- AG Photobiotechnologie, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Thomas Happe
- AG Photobiotechnologie, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Rana Hussein
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany
| | - Dieter Suter
- Experimentelle Physik, Technische Universität Dortmund, Emil-Figge-Straße 50, 44221 Dortmund, Germany
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Edward J. Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| |
Collapse
|
7
|
Dayan N, Ishay Y, Artzi Y, Cristea D, Reijerse E, Kuppusamy P, Blank A. Advanced surface resonators for electron spin resonance of single microcrystals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:124707. [PMID: 30599630 DOI: 10.1063/1.5063367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Electron spin resonance (ESR) spectroscopy of paramagnetic species in single crystals is a powerful tool for characterizing the latter's magnetic interaction parameters in detail. Conventional ESR systems are optimized for millimeter-size samples and make use of cavities and resonators that accommodate tubes and capillaries in the range 1-5 mm. Unfortunately, in the case of many interesting materials such as enzymes and inorganic catalytic materials (e.g., zeolites), single crystals can only be obtained in micron-scale sizes (1-200 µm). To boost ESR sensitivity and to enable experiments on microcrystals, the ESR resonator needs to be adapted to the size and shape of these specific samples. Here, we present a unique family of miniature surface resonators, known as "ParPar" resonators, whose mode volume and shape are optimized for such micron-scale single crystals. This approach significantly improves upon the samples' filling factor and thus enables the measurement of much smaller crystals than was previously possible. We present here the design of such resonators with a typical mode dimension of 20-50 µm, as well as details about their fabrication and testing methods. The devices' resonant mode(s) are characterized by ESR microimaging and compared to the theoretical calculations. Moreover, experimental ESR spectra of single microcrystals with typical sizes of ∼25-50 µm are presented. The measured spin sensitivity for the 50-µm resonator at cryogenic temperatures of 50 K is found to be ∼1.8 × 106 spins/G √Hz for a Cu-doped single crystal sample that is representative of many biological samples of relevance.
Collapse
Affiliation(s)
- Nir Dayan
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yakir Ishay
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yaron Artzi
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - David Cristea
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Edward Reijerse
- Max-Planck-Institut fuer Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Muelheim an der Ruhr, Germany
| | - Periannan Kuppusamy
- Department of Radiology and Medicine, Geisel School of Medicine, Dartmouth College, Lebanon, New Hampshire 03756, USA
| | - Aharon Blank
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| |
Collapse
|
8
|
Matheoud AV, Sahin N, Boero G. A single chip electron spin resonance detector based on a single high electron mobility transistor. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 294:59-70. [PMID: 30005194 DOI: 10.1016/j.jmr.2018.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Single-chip microwave oscillators are promising devices for inductive electron spin resonance spectroscopy (ESR) experiments on nanoliter and subnanoliter samples. Two major problems of the previously reported designs were the large minimum microwave magnetic field (0.1-0.7 mT) and large power consumption (0.5-200 mW), severely limiting their use for the investigation of samples having long relaxation times and for operation at low temperatures. Here we report on the design and characterization of a single-chip ESR detector operating with a microwave magnetic field and a power consumption orders of magnitude lower compared with previous designs. These significant improvements are mainly due to the use of a high electron mobility transistor (HEMT) technology instead of a complementary metal-oxide semiconductor (CMOS) technology. The realized single-chip ESR detector, which operates at 11.2 GHz, consists of an LC Colpitts oscillator realized with a single high-electron mobility transistor and a co-integrated single turn planar coil having a diameter of 440 μm. The realized detector operates from 300 K down to 1.4 K, at least. Its minimum microwave magnetic field is 0.4 μT at 300 K and 0.06 μT at 1.4 K, whereas its power consumption is 90 μW at 300 K and 4 μW at 1.4 K, respectively. The experimental spin sensitivity on a sensitive volume of about 30 nL, as measured with a single crystal of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, is of 8 × 1010 spins/Hz1/2 at 300 K and 2 × 109 spins/Hz1/2 at 10 K, respectively. In a volume of about 100 pL, located in proximity to the coil wire, the spin sensitivity improves by two orders of magnitude.
Collapse
Affiliation(s)
| | - Nergiz Sahin
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Giovanni Boero
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
| |
Collapse
|
9
|
Bouterfas M, Mouaziz S, Popovic RS. 14GHz longitudinally detected electron spin resonance using microHall sensors. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 282:47-53. [PMID: 28759742 DOI: 10.1016/j.jmr.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
In this work we developed a home-made LOngitudinally Detected Electron Spin Resonance (LODESR) spectrometer based on a microsize Hall sensor. A coplanar waveguide (CPW)-resonator is used to induce microwave-excitation on the sample at 14GHz. We used InSb cross-shaped Hall devices with active areas of (10μm×10μm) and (5μm×5μm). Signal intensities of the longitudinal magnetization component of DPPH and YIG samples of volumes about (10μm)3 and (5μm)3, are measured under amplitude and frequency modulated microwave magnetic field generated by the CPW-resonator. At room temperature, 109spins/G√Hz sensitivity is achieved for 0.2mT linewidth, a result which is still better than most of inductive detected LODESR sensitivities.
Collapse
Affiliation(s)
- M Bouterfas
- École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| | - S Mouaziz
- École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - R S Popovic
- École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| |
Collapse
|
10
|
Matheoud AV, Gualco G, Jeong M, Zivkovic I, Brugger J, Rønnow HM, Anders J, Boero G. Single-chip electron spin resonance detectors operating at 50GHz, 92GHz, and 146GHz. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 278:113-121. [PMID: 28388496 DOI: 10.1016/j.jmr.2017.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 06/07/2023]
Abstract
We report on the design and characterization of single-chip electron spin resonance (ESR) detectors operating at 50GHz, 92GHz, and 146GHz. The core of the single-chip ESR detectors is an integrated LC-oscillator, formed by a single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide semiconductor field effect transistors used as negative resistance network. On the same chip, a second, nominally identical, LC-oscillator together with a mixer and an output buffer are also integrated. Thanks to the slightly asymmetric capacitance of the mixer inputs, a signal at a few hundreds of MHz is obtained at the output of the mixer. The mixer is used for frequency down-conversion, with the aim to obtain an output signal at a frequency easily manageable off-chip. The coil diameters are 120μm, 70μm, and 45μm for the U-band, W-band, and the D-band oscillators, respectively. The experimental frequency noises at 100kHz offset from the carrier are 90Hz/Hz1/2, 300Hz/Hz1/2, and 700Hz/Hz1/2 at 300K, respectively. The ESR spectra are obtained by measuring the frequency variations of the single-chip oscillators as a function of the applied magnetic field. The experimental spin sensitivities, as measured with a sample of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, are 1×108spins/Hz1/2, 4×107spins/Hz1/2, 2×107spins/Hz1/2 at 300K, respectively. We also show the possibility to perform experiments up to 360GHz by means of the higher harmonics in the microwave field produced by the integrated single-chip LC-oscillators.
Collapse
Affiliation(s)
| | - Gabriele Gualco
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Minki Jeong
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Ivica Zivkovic
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Jürgen Brugger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Henrik M Rønnow
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | | | - Giovanni Boero
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Gualco G, Anders J, Sienkiewicz A, Alberti S, Forró L, Boero G. Cryogenic single-chip electron spin resonance detector. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 247:96-103. [PMID: 25261743 DOI: 10.1016/j.jmr.2014.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/12/2014] [Accepted: 08/25/2014] [Indexed: 06/03/2023]
Abstract
We report on the design and characterization of a single-chip electron spin resonance detector, operating at a frequency of about 20 GHz and in a temperature range extending at least from 300 K down to 4 K. The detector consists of an LC oscillator formed by a 200 μm diameter single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide-semiconductor field effect transistors used as negative resistance network. At 300 K, the oscillator has a frequency noise of 20 Hz/Hz(1/2) at 100 kHz offset from the 20 GHz carrier. At 4 K, the frequency noise is about 1 Hz/Hz(1/2) at 10 kHz offset. The spin sensitivity measured with a sample of DPPH is 10(8)spins/Hz(1/2) at 300 K and down to 10(6)spins/Hz(1/2) at 4 K.
Collapse
Affiliation(s)
- Gabriele Gualco
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jens Anders
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Andrzej Sienkiewicz
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Stefano Alberti
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - László Forró
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Giovanni Boero
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| |
Collapse
|