scholarly journals The paramagnetism of the ferromagnetic elements

1938 ◽  
Vol 167 (929) ◽  
pp. 189-204 ◽  
Keyword(s):  
Quantum Theory ◽  
Magnetic Moment ◽  
Curie Point ◽  
Low Temperatures ◽  
Experimental Results ◽  
Theoretical Development ◽  
Accurate Data ◽  
Iron Cobalt ◽  
Theory And Experiment ◽  
Cobalt And Nickel

The theory of paramagnetism, originally developed by Langevin (1905) and extended by Weiss (1907) to include ferromagnetics, led to expressions giving the variation of magnetization with temperature above and below the Curie point. These proved of great value in correlating experimental results, and the general agreement between theory and experiment leaves no doubt of the essential correctness of the ideas involved. However, with the introduction of the quantum theory, the nature of the elementary carriers of magnetic moment became apparent, and new values of atomic moments were calculated from the variation of susceptibility with temperature above the Curie point. The chief problem has been to reconcile these with the values more directly measured at low temperatures. Whilst the saturation intensities of the three ferromagnetics–iron, cobalt and nickel—are known with reasonable certainty, the susceptibility measurements of several workers on iron and cobalt show such large discrepancies that, except for nickel, the theoretical development has been considerably hampered by lack of sufficiently accurate data.

scholarly journals Weak-value amplification: state of play

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
George C. Knee ◽  
Joshua Combes ◽  
Christopher Ferrie ◽  
Erik M. Gauger
Keyword(s):  
Quantum Theory ◽  
Signal Amplification ◽  
Weak Measurement ◽  
Experimental Results ◽  
Weak Values ◽  
Theoretical Studies ◽  
Weak Value ◽  
Metrological Performance ◽  
Weak Value Amplification ◽  
Theory And Experiment

AbstractWeak values arise in quantum theory when the result of a weak measurement is conditioned on a subsequent strong measurement. The majority of the trials are discarded, leaving only very few successful events. Intriguingly those can display a substantial signal amplification. This raises the question of whether weak values carry potential to improve the performance of quantum sensors, and indeed a number of impressive experimental results suggested this may be the case. By contrast, recent theoretical studies have found the opposite: using weak-values to obtain an amplification generally worsens metrological performance. This survey summarises the implications of those studies, which call for a reappraisal of weak values’ utility and for further work to reconcile theory and experiment.

scholarly journals Kondo effect and superconductivity in niobium with iron impurities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hansong Zeng ◽  
Dan Zhou ◽  
Guoqing Liang ◽  
Rujun Tang ◽  
Zhi H. Hang ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Low Temperatures ◽  
Kondo Effect ◽  
Film Structure ◽  
Kondo Temperature ◽  
Superconducting Transition ◽  
Interesting Phenomenon ◽  
Superconducting Device ◽  
Bcc Lattice ◽  
Device Applications

AbstractKondo effect is an interesting phenomenon in quantum many-body physics. Niobium (Nb) is a conventional superconductor important for many superconducting device applications. It was long thought that the Kondo effect cannot be observed in Nb because the magnetic moment of a magnetic impurity, e.g. iron (Fe), would have been quenched in Nb. Here we report an observation of the Kondo effect in a Nb thin film structure. We found that by co-annealing Nb films with Fe in Argon gas at above 400 $$^{\circ }$$ ∘ C for an hour, one can induce a Kondo effect in Nb. The Kondo effect is more pronounced at higher annealing temperature. The temperature dependence of the resistance suggests existence of remnant superconductivity at low temperatures even though the system never becomes superconducting. We find that the Hamann theory for the Kondo resistivity gives a satisfactory fitting to the result. The Hamann analysis gives a Kondo temperature for this Nb–Fe system at $$\sim $$ ∼ 16 K, well above the superconducting transition onset temperature 9 K of the starting Nb film, suggesting that the screening of the impurity spins is effective to allow Cooper pairs to form at low temperatures. We suggest that the mechanism by which the Fe impurities retain partially their magnetic moment is that they are located at the grain boundaries, not fully dissolved into the bcc lattice of Nb.

Progress in preparation and characterization of silylene iron, cobalt and nickel complexes

2021 ◽  
Author(s):  
Wenjing Yang ◽  
Yanhong Dong ◽  
Hongjian Sun ◽  
Xiaoyan Li
Keyword(s):  
Nickel Complexes ◽  
Electron Cloud ◽  
Synthesis And Characterization ◽  
Iron Cobalt ◽  
Cloud Density ◽  
Cobalt And Nickel

The synthesis and characterization of Fe, Co and Ni complexes supported by silylene ligands in recent ten years are summarized. Due to the decrease of electron cloud density on Si...

Atomic fluorescence study on iron, cobalt, and nickel

1969 ◽  
Vol 41 (3) ◽  
pp. 518-522 ◽  
Author(s):  
Jaroslav. Matousek ◽  
Vaclav. Sychra
Keyword(s):  
Fluorescence Study ◽  
Atomic Fluorescence ◽  
Iron Cobalt ◽  
Cobalt And Nickel

Unbalance Response of a Dual Rotor System: Theory and Experiment

1993 ◽  
Vol 115 (4) ◽  
pp. 427-435 ◽  
Author(s):  
K. Gupta ◽  
K. D. Gupta ◽  
K. Athre
Keyword(s):  
System Theory ◽  
Transfer Matrix ◽  
Mode Shape ◽  
Reasonable Agreement ◽  
Complex Variables ◽  
Rotor System ◽  
Experimental Results ◽  
Unbalance Response ◽  
Theoretical Results ◽  
Theory And Experiment

A dual rotor rig is developed and is briefly discussed. The rig is capable of simulating dynamically the two spool aeroengine, though it does not physically resemble the actual aeroengine configuration. Critical speeds, mode shape, and unbalance response are determined experimentally. An extended transfer matrix procedure in complex variables is developed for obtaining unbalance response of dual rotor system. Experimental results obtained are compared with theoretical results and are found to be in reasonable agreement.

The statistical thermodynamics of solutions of non-spherical molecules. I. The thermodynamic functions

1955 ◽  
Vol 229 (1177) ◽  
pp. 271-280 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Equation Of State ◽  
Thermodynamic Functions ◽  
Statistical Thermodynamics ◽  
Intermolecular Forces ◽  
Pure Component ◽  
Experimental Results ◽  
Thermodynamics Of Solutions ◽  
Theory And Experiment

The perturbation treatment of the orientational forces between non-spherical molecules proposed by Cook & Rowlinson (1953) is extended to mixtures by using the theory of solutions put forward by Longuet-Higgins (1951). The thermodynamic functions and the equation of state of such mixtures are expressed in terms of the intermolecular forces and the properties of one pure component. Expressions are derived for the excess (or non-ideal) thermodynamic functions which are compared with the experimental results on the four solutions, benzene+ cyclohexane , benzene+carbon tetrachloride, benzene + ethylene dychloride, and cyclohexane + carbon tetrachloride. The agreement between theory and experiment is improved by taking account of the orientational forces.

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