scholarly journals Zum paramagnetischen Verhalten von Palladium/Silber/Eisen- Legierungen/ On the Paramagnetic Behaviour of Palladium-Silver-Iron Alloys

1975 ◽  
Vol 30 (5) ◽  
pp. 645-655
Author(s):  
Peter Brill
Keyword(s):  
Electron Concentration ◽  
Magnetic Moments ◽  
Alloy Series ◽  
Band Filling ◽  
Paramagnetic Behaviour ◽  
Field Coefficient ◽  
Saturation Moment ◽  
Molecular Field Coefficient ◽  
The Moment ◽  
Curie Temperatures

Abstract The paramagnetic susceptibility of four PdAgFe alloy series containing 1, 3, 5 and 7 at. % Fe have been measured between 20° and 150 °C. On the basis of a band filling model the local moment contribution to the susceptibility has been evaluated according to a Curie -Weiss law. Assuming that the iron atoms donate 3 electrons and the silver atoms 1 electron to the Pd 4d band, the effective magnetic moments and the paramagnetic Curie temperatures of all the alloys can be represented by a single curve against the electron concentration. The effective magnetic moment is consistent with an Fe moment of 5.92 μB localized on the iron sites and a Pd moment varying with electron concentration and temperature. The same turns out to be true for the ferromagnetic region where the saturation moment, obtained on PdFe alloys and a PdAgFe alloy by different authors, is considered to arise from a localized Fe moment of 5 μB and a concentration dependent Pd moment. The molecular field coefficient for the interaction between the Fe moments and the Pd 4d electrons is found to be 850 mol/cm3 at 385 K and 1200 mol/cm3 at 0 K. Finally, the iron moment suggested in this work is contrasted with the moment derived from neutron diffraction measurements.

Magnetic properties of (NixCu1−x)2MnSn

1977 ◽  
Vol 55 (17) ◽  
pp. 1481-1484 ◽  
Author(s):  
R. A. MacDonald ◽  
C. V. Stager
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Heusler Alloy ◽  
Room Temperature ◽  
Manganese Atom ◽  
Lattice Parameter ◽  
Alloy Series ◽  
Saturation Moment ◽  
Curie Temperatures

Magnetization and crystallographic measurements are reported for the Heusler alloy series (NixCu1−x)2MnSn. With the exception of Cu2MnSn and perhaps (Ni0.1Cu0.9)2MnSn all of the samples prepared had the cubic Heusler L21 structure at room temperature. The lattice parameter varies linearly as a function of composition. The saturation moment is constant at approximately 4μβ per manganese atom throughout the series. Curie temperatures vary smoothly but non-linearly with composition, providing some evidence for at least two competing mechanisms in the determination of the Curie temperature.

scholarly journals Doppler Shift of Radio Signals Transmitted between Orbiting Satellites

1982 ◽  
Vol 35 (2) ◽  
pp. 155 ◽  
Author(s):  
PL Dyson ◽  
JA Bennett
Keyword(s):  
Electron Concentration ◽  
Doppler Shift ◽  
Rate Of Change ◽  
Line Of Sight ◽  
Concentration Gradients ◽  
Mean Velocity ◽  
Radio Signals ◽  
The Mean ◽  
The Moment ◽  
The Individual

A general expression, applicable at VHF and above, is derived for the Doppler shift of radio signals transmitted between two satellites embedded in the ionosphere. The Doppler shift is made up of several contributions which depend on (a) the rate of change of the free space path between the satellites, (b) the components, perpendicular to the line of sight between the satellites, of both the mean velocity of the satellites and the electron concentration gradients, (c) the moment of the perpendicular electron concentration gradients and the deviations from the mean of the individual satellite perpendicular velocities, (d) the velocity components along the line of sight between the satellites, and the electron concentration values at each satellite, and (e) changes occurring in the ionosphere with time.

DISCOVERY OF DICKE SUPERRADIATION BY SYSTEM OF NUCLEAR MAGNETIC MOMENTS

1988 ◽  
Vol 01 (11n12) ◽  
pp. 409-416 ◽  
Author(s):  
J.F. KISELEV ◽  
A.F. PRUDKOGLYAD ◽  
A.S. SHUMOVSKY ◽  
V.I. YUKALOV
Keyword(s):  
Radio Frequency ◽  
Resonance Frequency ◽  
Low Temperatures ◽  
Magnetic Moments ◽  
Larmor Frequency ◽  
Coherent Radiation ◽  
Spontaneous Generation ◽  
Oscillatory Circuit ◽  
Nuclear Magnetic Moments ◽  
The Moment

Spontaneous generation of the Dicke superradiation (SR) state has been found in the system of inversely polarised proton spins with “frozen” polarisation. SR is observed at the moment when the Larmor frequency crosses the resonance frequency of the passive oscillatory circuit. SR arises from incoherent maser generation of spins. The frequency of a SR generator can be retuned from several hundreds of kilohertz to hundreds of megahertz at very low temperatures. Dependence of incoherent and coherent radiation on the initial polarisation has been investigated. A radio frequency analogue of the optical SR laser is shown to be possible both for weak-amplifying and for strong-amplifying active media, depending on the factor of filling and polarisation of nuclei. SR-reverse of negative polarisation is observed in the latter case.

Magnetic Properties of Compounds RE2Cu2Mg (RE = Y, La, Pr, Nd)

2003 ◽  
Vol 58 (6) ◽  
pp. 497-500 ◽  
Author(s):  
Gunter Kotzybaa ◽  
Ratikanta Mishrab ◽  
Rainer Pöttgena
Keyword(s):  
Magnetic Properties ◽  
High Frequency ◽  
Remanent Magnetization ◽  
Magnetic Transition ◽  
Magnetic Moments ◽  
Temperature Dependent ◽  
Furnace Temperature ◽  
Pauli Paramagnetism ◽  
Magnetization Behavior ◽  
Curie Temperatures

The Mo2FeB2 type magnesium intermetallics RE2Cu2Mg (RE = Y, La, Pr, Nd) were synthesized from the elements by reactions in sealed tantalum tubes in a high-frequency furnace. Temperature-dependent magnetic susceptibility measurements of Y2Cu2Mg and La2Cu2Mg indicate Pauli paramagnetism. Pr2Cu2Mg and Nd2Cu2Mg show Curie-Weiss behaviour with experimental magnetic moments of 3.67(2) μB/Pr and 3.47(2) μB/Nd, respectively. Both compounds are ordered ferromagnetically at Curie temperatures of 12.0(5) (Pr2Cu2Mg) and 43.0(5) K (Nd2Cu2Mg). Pr2Cu2Mg shows a very complex magnetization behavior with an additional magnetic transition around 2.5 T. The neodymium compound shows a pronounced square loop behavior in the magnetization at 4.5 K with a high remanent magnetization of 1.55(1) μB/Nd atom and a coercive field of 0.31(1) T.

Localized canting model for substituted ferrimagnets. I. Singly substituted YIG systems

1970 ◽  
Vol 48 (23) ◽  
pp. 2857-2867 ◽  
Author(s):  
A. Rosencwaig
Keyword(s):  
Experimental Data ◽  
Magnetic Properties ◽  
Statistical Model ◽  
Magnetic Moments ◽  
Exchange Parameter ◽  
New Model ◽  
Model Based ◽  
Curie Temperatures ◽  
Good Agreement

A statistical model based on the concept of localized canting, originally proposed by Geller and coworkers, is developed to account for the magnetic properties of substituted ferrimagnets. This model is used to determine the exchange parameter ratios Jdd/Jdd and Jaa/Jad in YIG systems by evaluating the magnetic moments and Curie temperatures of two classes of singly substituted YIG over the entire substitution range. Good agreement with experimental data is obtained with the physically reasonable exchange parameter ratios of [Formula: see text] and Jaa/Jad *~ 0.07. It is also shown that both the Yafet-Kittel and the Nowik models may be regarded as particular limiting cases of the new model.

IRON INFLUENCE ON OPTICAL AND MAGNETIC PROPERTIES OF LEAD-BISMUTHATE GLASSES

2003 ◽  
Vol 17 (05n06) ◽  
pp. 235-244
Author(s):  
V. SIMON ◽  
R. POP ◽  
N. N. PUŞCAŞ
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moments ◽  
Magnetic Interaction ◽  
Infrared Range ◽  
Matrix Formalism ◽  
Iron Ions ◽  
Density Matrix Formalism ◽  
Optical And Magnetic Properties ◽  
Experimental Values ◽  
Curie Temperatures

Results concerning the structural, optical and magnetic properties of x Fe 2 O 3 · (100 - x)[3 Bi 2 O 3 · 2 PbO ] glasses (0 = x = 20 mol%) are reported. The transparence in the infrared range was investigated. The homogeneous absorption cross section was determined from the optical absorption spectra using the density matrix formalism of the McCumber theoretical model. From the temperature dependence of reciprocal magnetic susceptibility, negative paramagnetic Curie temperatures have been found suggesting the antiferromagnetic nature of the magnetic interaction between the iron ions in the studied samples. The iron ions occur both in the (II) and (III) valence state. The Fe 2+/ Fe 3+ ratio was determined from the experimental values of the magnetic moments for all samples. The glass transition temperature with increasing Fe 2 O 3 content was also investigated.

MAGNETIC MOMENT OF 2-DIMENSIONAL AND 3-DIMENSIONAL MANY-ELECTRON SYSTEMS EXAMINED WITH DEPENDENCE ON A COMMON SIZE PARAMETER

2002 ◽  
Vol 16 (30) ◽  
pp. 1183-1191
Author(s):  
S. OLSZEWSKI
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Electron Gas ◽  
Three Dimensional ◽  
Electron Systems ◽  
Size Parameter ◽  
3 Dimensional ◽  
Cubic Lattice ◽  
Simple Cubic ◽  
The Moment

The orbital magnetic moments induced by a constant magnetic field in a two-dimensional (2D) and three-dimensional (3D) electron gas are calculated on the same footing independent of the conventional method based on statistical thermodynamics. The dependence of the moment on a common size parameter — defined as the cubic root of the volume occupied by one electron in a 3D gas — is found to be a similar monotonic function for both kinds of electron gas. This monotonic dependence is compared with the oscillating function of the size parameter obtained for the magnetic moment calculated in the case of a 2D slice of the tightly-bound s-electron states in a simple-cubic, or body-centred cubic, lattice.

scholarly journals Magnetic dating of the Holocene monogenetic Tkarsheti volcano in the Kazbeki region (Great Caucasus)

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Goga Vashakidze ◽  
Avto Goguitchaichvili ◽  
Natalia García-Redondo ◽  
Manuel Calvo-Rathert ◽  
Ángel Carrancho ◽  
...  
Keyword(s):  
Lava Flow ◽  
Remanent Magnetization ◽  
Time Intervals ◽  
The Caucasus ◽  
Monogenetic Volcano ◽  
Significant Difference ◽  
Paleomagnetic Dating ◽  
The Mean ◽  
The Moment ◽  
Curie Temperatures

AbstractThe radiocarbon technique is widely used to date Late Pleistocene and Holocene lava flows. The significant difference with palaeomagnetic methods is that the 14C dating is performed on the organic matter carbonized by the rock formation or the paleosols found within or below the lava flow. On the contrary, the archaeomagnetic dating allows to date the moment when the lava is cooling down below the Curie temperatures. In the present study, we use the paleomagnetic dating to constrain the age of the Tkarsheti monogenetic volcano located within the Kazbeki Volcanic Province (Great Caucasus). A series of rock-magnetic experiments including the measurement of hysteresis curves, isothermal remanence, back-field and continuous thermomagnetic curves were applied. These experiments indicated that Pseudo-Single-Domain Ti-poor titanomagnetite is responsible for remanence. A characteristic remanent magnetization was obtained for all twenty analyzed samples yielding a stable single magnetization component observed upon both thermal and alternating field treatments. Comparison of the mean directions obtained (Inc = 48.6º, Dec = 6.4º, A95 = 4.0° and K = 67) with the SCHA.DIF.14k model yielded two main time intervals (4740–4650 or 4427–4188 BC) as the best age estimate of the Lesser Tkarsheti lava flow. These results suggest an earlier age (between approximately 200 and 700 years) for this monogenetic lava flow than expected from the estimated age provided by a former 14C dating obtained in 1973 on woody remains. This first attempt to use the archaeomagnetic technique in the Caucasus indicates that the SCHA.DIF.14k geomagnetic model may be successfully used for dating purposes in the region .

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