14 results on '"Felix, Fuhrmann"'
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2. Selective Recognition of Ammonium over Potassium Ion with Acyclic Receptor Molecules Bearing 3,4,5-Trialkylpyrazolyl Groups
- Author
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Felix Fuhrmann, Wilhelm Seichter, and Monika Mazik
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molecular recognition ,ammonium receptors ,selectivity ,structure–binding activity relationships ,Chemistry ,QD1-999 - Abstract
Abstract Among the 1,3,5-trisubstituted 2,4,6-triethylbenzenes bearing pyrazolyl groups, the compounds with 3,5-dimethylpyrazolyl moieties were found to be effective receptors for ammonium ions (NH4 +). The current study investigated the extent to which the incorporation of an additional alkyl group in the 4-position of the pyrazole ring affects the binding properties of the new compounds. 1H NMR spectroscopic titrations and investigations using isothermal titration calorimetry revealed that this small structural variation leads to a significant increase in the binding strength towards NH4 + and also improves the binding preference for NH4 + over K+. In addition to the studies in solution, crystalline complexes of the new triethyl- and trimethylbenzene derivatives, bearing 3,4,5-trialkylpyrazolyl groups, with NH4 +PF6 − were obtained and analyzed in detail. It is noteworthy that two of the crystal structures discussed in this work are characterized by the presence of two types of ammonium complexes. Studies focusing on the development of new artificial ammonium receptors are motivated, among other things, by the need for more selective ammonium sensors than those based on the natural ionophore nonactin.
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- 2022
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3. Energiespeicher: Aluminium statt Lithium
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Ulrike Wunderwald, Peter von Czarnecki, Martin Eckert, Charan Mukundan, Gero Frisch, Jean‐François Drillet, Felix Fuhrmann, and Franziska Jach
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General Chemical Engineering ,General Chemistry - Published
- 2022
4. Magnon detection using a ferroic collinear multilayer spin valve
- Author
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Joel Cramer, Felix Fuhrmann, Ulrike Ritzmann, Vanessa Gall, Tomohiko Niizeki, Rafael Ramos, Zhiyong Qiu, Dazhi Hou, Takashi Kikkawa, Jairo Sinova, Ulrich Nowak, Eiji Saitoh, and Mathias Kläui
- Subjects
Science - Abstract
The Joule heating free magnon spintronics advances conventional electronics but demands more magnon-based logic operations. Here the authors achieved the magnon spin valve functionality in a YIG/CoO/Co structure where the amplitude of transmitted magnon from the YIG layer is dependent on the relative alignment of the YIG and Co magnetization.
- Published
- 2018
- Full Text
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5. Crystal structure of the complex of 2,4,6-tri-ethyl-1,3,5-tris-[(4-methyl-1
- Author
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Felix, Fuhrmann, Eric, Meier, Wilhelm, Seichter, and Monika, Mazik
- Abstract
The complex of 2,4,6-tri-ethyl-1,3,5-tris-[(4-methyl-1
- Published
- 2022
6. Magnetic Coupling in Y3Fe5O12/Gd3Fe5O12 Heterostructures
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Jun Miao, J. B. Yang, Gerhard Jakob, Sven Becker, Zengyao Ren, Andrew Ross, Felix Fuhrmann, Rui Wu, Shilei Ding, S. Lord, and Mathias Kläui
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Condensed Matter::Materials Science ,Magnetization ,Materials science ,Magnetic moment ,Magnetoresistance ,Ferromagnetism ,Condensed matter physics ,Ferrimagnetism ,Magnon ,General Physics and Astronomy ,Condensed Matter::Strongly Correlated Electrons ,Coupling (probability) ,Inductive coupling - Abstract
Ferrimagnetic ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (YIG) is the prototypical material for studying magnonic properties due to its exceptionally low damping. By substituting the yttrium with rare earth elements that have a net magnetic moment, we can introduce an additional spin degree of freedom. Here, we study the magnetic coupling in epitaxial ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$/${\mathrm{Gd}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (YIG/GIG) heterostructures grown by pulsed laser deposition. From bulk sensitive magnetometry and surface sensitive spin Seebeck effect and spin Hall magnetoresistance measurements, we determine the alignment of the heterostructure magnetization as a function temperature and external magnetic field. The ferromagnetic coupling between the $\mathrm{Fe}$ sublattices of YIG and GIG dominates the overall behavior of the heterostructures. Because of the temperature-dependent gadolinium moment, a magnetic compensation point of the total bilayer system can be identified. This compensation point shifts to lower temperatures with increasing YIG thickness due the parallel alignment of the iron moments. We show that we can control the magnetic properties of the heterostructures by tuning the thickness of the individual layers, opening up a large playground for magnonic devices based on coupled magnetic insulators. These devices could potentially control the magnon transport analogously to electron transport in giant magnetoresistive devices.
- Published
- 2021
7. Mechanism of Néel Order Switching in Antiferromagnetic Thin Films Revealed by Magnetotransport and Direct Imaging
- Author
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Francesco Maccherozzi, Eiji Saitoh, Sergio Valencia, Olena Gomonay, Jairo Sinova, Rafael Ramos, M. Filianina, Andrew Ross, Lorenzo Baldrati, Romain Lebrun, Felix Fuhrmann, C. Leveille, Mathias Kläui, Florian Kronast, T. R. Forrest, and Mainz, Johannes Gutenberg-Universität
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Condensed Matter - Materials Science ,Materials science ,Magnetoresistance ,Condensed matter physics ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,General Physics and Astronomy ,Large scale facilities for research with photons neutrons and ions ,Direct imaging ,01 natural sciences ,3. Good health ,Magnetic anisotropy ,Order (biology) ,Domain wall (magnetism) ,0103 physical sciences ,Torque ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Thin film ,010306 general physics ,Spin-½ - Abstract
We probe the current-induced magnetic switching of insulating antiferromagnet/heavy metals systems, by electrical spin Hall magnetoresistance measurements and direct imaging, identifying a reversal occurring by domain wall (DW) motion. We observe switching of more than one third of the antiferromagnetic domains by the application of current pulses. Our data reveal two different magnetic switching mechanisms leading together to an efficient switching, namely the spin-current induced effective magnetic anisotropy variation and the action of the spin torque on the DWs., 26 pages, including supplementary material
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- 2019
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8. Magnon detection using a ferroic collinear multilayer spin valve
- Author
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Felix Fuhrmann, Vanessa Gall, Eiji Saitoh, Mathias Kläui, Zhiyong Qiu, Takashi Kikkawa, Rafael Ramos, Jairo Sinova, Dazhi Hou, Joel Cramer, Ulrike Ritzmann, Tomohiko Niizeki, and Ulrich Nowak
- Subjects
Materials science ,Magnetoresistance ,530 Physics ,Science ,Spin valve ,General Physics and Astronomy ,02 engineering and technology ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Magnetization ,Condensed Matter::Materials Science ,Spin wave ,0103 physical sciences ,ddc:530 ,010306 general physics ,lcsh:Science ,Spin-½ ,Multidisciplinary ,Condensed matter physics ,Spintronics ,Condensed Matter::Other ,Magnon ,General Chemistry ,021001 nanoscience & nanotechnology ,530 Physik ,Ferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,lcsh:Q ,0210 nano-technology - Abstract
Information transport and processing by pure magnonic spin currents in insulators is a promising alternative to conventional charge-current-driven spintronic devices. The absence of Joule heating and reduced spin wave damping in insulating ferromagnets have been suggested for implementing efficient logic devices. After the successful demonstration of a majority gate based on the superposition of spin waves, further components are required to perform complex logic operations. Here, we report on magnetization orientation-dependent spin current detection signals in collinear magnetic multilayers inspired by the functionality of a conventional spin valve. In Y3Fe5O12|CoO|Co, we find that the detection amplitude of spin currents emitted by ferromagnetic resonance spin pumping depends on the relative alignment of the Y3Fe5O12 and Co magnetization. This yields a spin valve-like behavior with an amplitude change of 120% in our systems. We demonstrate the reliability of the effect and identify its origin by both temperature-dependent and power-dependent measurements., The Joule heating free magnon spintronics advances conventional electronics but demands more magnon-based logic operations. Here the authors achieved the magnon spin valve functionality in a YIG/CoO/Co structure where the amplitude of transmitted magnon from the YIG layer is dependent on the relative alignment of the YIG and Co magnetization.
- Published
- 2018
9. Complex Terahertz and Direct Current Inverse Spin Hall Effect in YIG/Cu1-xIrx Bilayers Across a Wide Concentration Range
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Martin Jourdan, Tom Seifert, Gerhard Jakob, Alexander Kronenberg, Felix Fuhrmann, Tobias Kampfrath, Joel Cramer, and Mathias Kläui
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Physics ,Spintronics ,Condensed matter physics ,Terahertz radiation ,Mechanical Engineering ,Direct current ,Yttrium iron garnet ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Thermoelectric effect ,Spin Hall effect ,General Materials Science ,Thin film ,010306 general physics ,0210 nano-technology ,Spin-½ - Abstract
We measure the inverse spin Hall effect of Cu1-xIrx thin films on yttrium iron garnet over a wide range of Ir concentrations (0.05 ⩽ x ⩽ 0.7). Spin currents are triggered through the spin Seebeck effect, either by a continuous (dc) temperature gradient or by ultrafast optical heating of the metal layer. The spin Hall current is detected by electrical contacts or measurement of the emitted terahertz radiation. With both approaches, we reveal the same Ir concentration dependence that follows a novel complex, nonmonotonous behavior as compared to previous studies. For small Ir concentrations a signal minimum is observed, whereas a pronounced maximum appears near the equiatomic composition. We identify this behavior as originating from the interplay of different spin Hall mechanisms as well as a concentration-dependent variation of the integrated spin current density in Cu1-xIrx. The coinciding results obtained for dc and ultrafast stimuli provide further support that the spin Seebeck effect extends to terahertz frequencies, thus enabling a transfer of established spintronic measurement schemes into the terahertz regime. Our findings also show that the studied material allows for efficient spin-to-charge conversion even on ultrafast time scales.
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- 2018
10. Complex Terahertz and Direct Current Inverse Spin Hall Effect in YIG/Cu
- Author
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Joel, Cramer, Tom, Seifert, Alexander, Kronenberg, Felix, Fuhrmann, Gerhard, Jakob, Martin, Jourdan, Tobias, Kampfrath, and Mathias, Kläui
- Abstract
We measure the inverse spin Hall effect of Cu
- Published
- 2018
11. Laser‐Induced Creation of Antiferromagnetic 180‐Degree Domains in NiO/Pt Bilayers.
- Author
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Meer, Hendrik, Wust, Stephan, Schmitt, Christin, Herrgen, Paul, Fuhrmann, Felix, Hirtle, Steffen, Bednarz, Beatrice, Rajan, Adithya, Ramos, Rafael, Niño, Miguel Angel, Foerster, Michael, Kronast, Florian, Kleibert, Armin, Rethfeld, Baerbel, Saitoh, Eiji, Stadtmüller, Benjamin, Aeschlimann, Martin, and Kläui, Mathias
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LINEAR dichroism ,OPTICAL switching ,THIN films ,IRRADIATION ,HETEROSTRUCTURES ,DICHROISM - Abstract
The antiferromagnetic order in heterostructures of NiO/Pt thin films can be modified by optical pulses. After the irradiation with laser light, the optically induced creation of antiferromagnetic domains can be observed by imaging the created domain structure utilizing the X‐ray magnetic linear dichroism effect. The effect of different laser polarizations on the domain formation can be studied and used to identify a polarization‐independent creation of 180° domain walls and domains with 180° different Néel vector orientation. By varying the irradiation parameters, the switching mechanism can be determined to be thermally induced. This study demonstrates experimentally the possibility to optically create antiferromagnetic domains, an important step towards future functionalization of all optical switching mechanisms in antiferromagnets. [ABSTRACT FROM AUTHOR]
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- 2023
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12. Energiespeicher: Aluminium statt Lithium.
- Author
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Wunderwald, Ulrike, von Czarnecki, Peter, Eckert, Martin, Mukundan, Charan, Frisch, Gero, Drillet, Jean‐François, Fuhrmann, Felix, and Jach, Franziska
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ENERGY storage ,CLEAN energy ,POWER density ,POWER resources ,ENERGY density - Abstract
Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
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13. Crystal structure of the complex of 2,4,6-triethyl-1,3,5-tris[(4-methyl-1H-indazol-1-yl)methyl]-benzene with NH4PF6.
- Author
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Fuhrmann, Felix, Meier, Eric, Seichter, Wilhelm, and Mazik, Monika
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CRYSTAL structure ,COMPLEX ions ,AMMONIUM ions ,SPACE groups ,BINDING sites ,HYDROGEN atom - Abstract
The complex of 2,4,6-triethyl-1,3,5-tris[(4-methyl-1H-indazol-1-yl)methyl]benzene with ammonium hexafluorophosphate, C
39 H42 N6 ·NH4 + ·PF6 - , crystallizes in the monoclinic space group P21 with two molecules of the receptor, two NH4 + and two PF6 - ions in the asymmetric unit. In each of the complexes the ammonium ion resides in the cavity of the receptor molecule and is fixed in its position by three N--H⋯N bonds, while the remaining hydrogen atom of the cation acts as a bifurcated binding site for N--H⋯F bonding to the counter-anion. The crystal is composed of one-dimensional supramolecular aggregates extending along the a-axis direction. [ABSTRACT FROM AUTHOR]- Published
- 2022
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14. Germans to America, Jan. 2, 1850-May 24, 1851 : Lists of Passengers Arriving at U.S. Ports
- Author
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Ira A. Glazier, William P. Filby, Ira A. Glazier, and William P. Filby
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- Immigrants--United States--Registers, Ships--United States--Passenger lists, German Americans--Genealogy
- Abstract
Germans to America provides both genealogists and researchers of family history with the first extensive, indexed source of German-surname immigrants who came to all ports in the United States between 1850 and 1893. This period witnessed one of the highest rates of German emigration in the nineteenth century. The series reproduces information from the original ship manifest schedules, or passenger lists, filed by all vessels entering U.S. ports. All volumes are arranged in chronologi-cal order by each ship's date of arrival. For every passenger list, the following information is provided: ship name, port of departure, port of arrival, date of arrival, and list of German-surname passengers. Ships that departed from German ports or carried passengers who declared themselves to be of German origin are included, with full name, age, sex, occupation, and, when this information is given, country, province or village of origin provided for each emigrant. One of the most important features of this series is the complete index of names at the end of every volume, making it easy to find a particular individual or family name. Germans to America may be ordered by individual volume. Standing orders, which receive a 10% discount, are also welcomed.
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- 1988
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