scholarly journals Paramagnetic Resonance as a Probe of the Spin Gap in Normal State of Superconductor

2011 ◽  
Vol 2011 ◽  
pp. 1-3
Author(s):  
Frank J. Owens
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Transition Temperature ◽  
Normal State ◽  
Oxide Superconductors ◽  
Superconducting Transition ◽  
Paramagnetic Resonance ◽  
Spin Gap ◽  
Order Of Magnitude ◽  
Copper Oxide Superconductors ◽  
Electron Paramagnetic

It is shown that electron paramagnetic resonance (EPR) can be used to observe the spin gap in copper oxide superconductors. The electron paramagnetic resonance spectra of the Cu2+ ion in underdoped show a pronounced decrease in intensity in the normal state as the temperature is lowered to 133 K, the superconducting transition temperature of the material. The decrease is attributed to a pairing of the Cu2+   spins to form a spin gap. A spin gap of 0.0533 eV is estimated from the data which is in order of magnitude agreement with values obtained from NMR measurements.

Epr Spectroscopy on Zn-Substituted YBa2Cu3O7

1987 ◽  
Vol 99 ◽  
Author(s):  
A. M. Ponte Goncalves ◽  
Chan-Soo Jee ◽  
D. Nichols ◽  
J. E. Crow ◽  
G. H. Myer ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Transition Temperature ◽  
Epr Spectroscopy ◽  
Superconducting Transition Temperature ◽  
Superconducting Phase ◽  
Superconducting Transition ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Cu Ions ◽  
Bulk Response

ABSTRACTThe temperature and concentration dependence of the electron paramagnetic resonance spectra of YBa2(Cu1−xZnx)3O7 has been measured for 0≤x≤0.16. Zn substituted on the Cu-site cause a rapid nearly linear depression of the superconducting transition temperature Tc with Tc going to zero in the vicinity of x=0.10. Only weak EPR spectra due to ≤1% of the Cu-ions are seen in the superconducting phase of YBa2Cu3O7. These spectra are most likely attributed to Cu-ions in the vicinity of grain boundaries and do not represent a bulk response. However, a strong asymmetric resonance is observed in the Zn-substituted samples with x>0.1. The EPR results obtained for YBa2(Cu1−xZnx)3O7 are discussed in terms of a possible localization of d-electrons.

Epr of Mn2+ in Ni(CH3COO)2 4H2O and K2 Ni(SO4)2 6H2O

1980 ◽  
Vol 3 ◽  
Author(s):  
Sushil K. Misra ◽  
M. Jalochowski
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Properties ◽  
Transition Temperature ◽  
Single Crystals ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

ABSTRACTThe technique of electron paramagnetic resonance has been applied to study the magnetic properties of nickel acetate and nickel potassium tutton salt single crystals, using Mn2+ ion as probe. From the values of spin Hamiltonian parameters and linewidths at room, liquid nitrogen and liquid helium temperatures it is concluded that these crystals do not become magnetically ordered as the temperature is lowered to 3.2K, and thus the transition temperature, below which the crystal would order either ferromagnetically, or antiferromagnetically, for these crystals, should be below 3.2K.

scholarly journals Nanomolar Pulse Dipolar EPR Spectroscopy in Proteins; the Copper(II)-Copper(II) and Nitroxide-Nitroxide Cases

2021 ◽  
Author(s):  
Katrin Ackermann ◽  
Joshua Wort ◽  
Bela Bode
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Geometric Constraints ◽  
Spin Labels ◽  
Paramagnetic Resonance ◽  
Frozen Solution ◽  
Model Protein ◽  
Concentration Sensitivity ◽  
Order Of Magnitude ◽  
Health And Disease ◽  
Electron Paramagnetic

The study of ever more complex biomolecular assemblies implicated in human health and disease is facilitated by a suite of complementary biophysical methods. Pulse Dipolar Electron Paramagnetic Resonance (PDEPR) spectroscopy is a powerful tool that provides highly precise geometric constraints in frozen solution, however the drive towards PDEPR at physiologically relevant sub-μM concentrations is limited by the currently achievable concentration sensitivity. Recently, PDEPR using a combination of nitroxide and Cu<sup>II</sup> based spin labels allowed measuring 500 nM concentration of a model protein. Using commercial instrumentation and spin labels we demonstrate Cu<sup>II</sup>-Cu<sup>II</sup> and nitroxide-nitroxide PDEPR measurements at protein concentrations more than an order of magnitude below previous examples reaching 500 and 100 nM, respectively. These results demonstrate the general feasibility of sub-μM PDEPR measurements at short to intermediate distances (~1.5 - 3.5 nm), and are of particular relevance for applications where the achievable concentration is limiting.

scholarly journals The Impact of Hydrogenation on Structural and Superconducting Properties of FeTe0.65Se0.35 Single Crystals

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7900
Author(s):  
Stanislav I. Bondarenko ◽  
Anatolij I. Prokhvatilov ◽  
Roman Puźniak ◽  
Jarosław Piętosa ◽  
Andrey A. Prokhorov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Structural Changes ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Paramagnetic Resonance ◽  
The Impact ◽  
Electron Paramagnetic ◽  
Diffusion Of Hydrogen

Properties of FeTe0.65Se0.35 single crystals, with the onset of critical temperature (Tconset) at 15.5 K, were modified via hydrogenation performed for 10–90 h, at temperatures ranging from 20 to 250 °C. It was found that the tetragonal matrix became unstable and crystal symmetry lowered for the samples hydrogenated already at 200 °C. However, matrix symmetry was not changed and the crystal was not destroyed after hydrogenation at 250 °C. Bulk Tcbulk, determined at the middle of the superconducting transition, which is equal to 12–13 K for the as grown FeTe0.65Se0.35, rose by more than 1 K after hydrogenation. The critical current density studied in magnetic field up to 70 kOe increased 4–30 times as a consequence of hydrogenation at 200 °C for 10 h. Electron paramagnetic resonance measurements also showed higher values of Tcbulk for hydrogenated crystals. Thermal diffusion of hydrogen into the crystals causes significant structural changes, leads to degeneration of crystal quality, and significantly alters superconducting properties. After hydrogenation, a strong correlation was noticed between the structural changes and changes in the parameters characterizing the superconducting state.

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