Negative imaginary component of AC magnetic susceptibility, metastable states, and magnetic relaxation in La0.6Sr0.35MnTi0.05O3

2020 ◽  
Vol 13 (04) ◽  
pp. 2050023
Author(s):  
Alexander N. Ulyanov ◽  
Duc-Quang Hoang ◽  
Natalia N. Kuznetsova ◽  
Seong-Cho Yu
Keyword(s):  
Landau Theory ◽  
Ac Susceptibility ◽  
Metastable States ◽  
Imaginary Component ◽  
Ac Magnetic Susceptibility ◽  
Relaxation Effects ◽  
Long Time ◽  
New Phase ◽  
Negative Formula ◽  
Intrinsic Feature

Off-stoichiometric ([Formula: see text][Formula: see text])([Formula: see text]) MnO3 manganite was studied with in-phase (real, [Formula: see text]) and out-of-phase (imaginary, [Formula: see text]) components of ac susceptibility measurements. Short- and long-time relaxation effects, manifested by the revealed negative [Formula: see text], were observed. The effects are explained at the frame of Landau theory of phase transitions where a coexistence of stable and metastable states is considered. It is supposed that the appearance of negative [Formula: see text] is an intrinsic feature of magnetic materials with impurities, defects and vacancies blocking nucleation and growth of new phase.

scholarly journals Military Coups d'etat in Nigeria Revisited: A Political and Economic Analysis

1993 ◽  
Vol 14 ◽  
pp. 129-147
Author(s):  
Julius E. Nyangoro
Keyword(s):  
South Africa ◽  
Military Intervention ◽  
Authoritarian Regimes ◽  
African Politics ◽  
Long Time ◽  
Racial Domination ◽  
Coups D'etat ◽  
New Phase ◽  
Radical Transformation

In the last few years, there seems to have been a radical transformation in African politics. South Africa, which for a long time reflected the politics of racial domination, is moving towards multi-racial rule. Formerly one-party states such as Zambia and Kenya recently have held multi-party elections; and authoritarian regimes such as Zaire are now seriously discussing the possibility of pluralist politics. The question that this paper seeks to address is whether the changes taking place are indeed ushering in a new phase of politics in Africa without the prospect of military intervention. Nigeria is used as a case study for examining this question.

THE EFFECT OF PARTIAL ATOMIC SUBSTITUTION ON ELECTRIC AND MAGNETIC PROPERTIES OF (Bi,Pb):2223 SINTERED SUPERCONDUCTORS

2003 ◽  
Vol 17 (26) ◽  
pp. 4675-4681 ◽  
Author(s):  
A. V. POP ◽  
M. POP ◽  
I. I. GERU
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Electrical Resistance ◽  
Ac Susceptibility ◽  
Partial Substitution ◽  
Superconducting Transition ◽  
Ac Magnetic Susceptibility ◽  
Atomic Concentration ◽  
Susceptibility Data ◽  
Atomic Substitution

The effect of partial substitution of Ca by x = 0.02 La on the electrical and magnetically properties of two (Bi,Pb):2223 superconductor ceramic S1 and S2 (with different Pb and Sr atomic concentration) were investigated by using electrical resistance and AC magnetic susceptibility measurements. The parameters from linear resistivity data in the normal state and superconducting transition are sensitive to the compounds stoechiomerty. The intergrain critical current density JcJ(T) dependence near Tc obtained from immaginary AC susceptibility data agrees with the assumption of SNS intergrain junctions.

scholarly journals Science underpinning the safety case of deep geological repositories − challenges in the past and in the future and how to maintain knowledge and competence during operation

2020 ◽  
Vol 6 ◽  
pp. 24
Author(s):  
Johan Andersson
Keyword(s):  
International Cooperation ◽  
Safety Assessment ◽  
Spent Nuclear Fuel ◽  
Research Strategy ◽  
Version Control ◽  
The Past ◽  
Safety Case ◽  
Long Time ◽  
New Challenges ◽  
New Phase

Final repositories for spent nuclear fuel are approaching implementation. A prerequisite for these advancements is that it has been shown that the repository can be constructed and operated in practice in such a way that safety can be assured both during operation and over very long time scales. The success rests on decades of structured and objective-driven research and development. A key element of the research strategy has been to ensure adequate in-house competence and expertise. Also, openness and international cooperation are essential. Workable procedures for data qualification, version control as well as internal and external peer review have gained importance. When the programmes now enter a new phase of construction and operation new challenges will arise. Even if the implementing organisations would need to keep a core competence on post closure safety assessment international cooperation will be even more important on developing, sharing and managing the knowledge needed.

Study of Microstructure and Phase Composition of Creep Resistant Cast Steel

2014 ◽  
Vol 782 ◽  
pp. 335-338
Author(s):  
Renata Chylińska ◽  
Małgorzata Garbiak ◽  
Bogdan Piekarski
Keyword(s):  
Phase Composition ◽  
Cast Steel ◽  
Annealing Process ◽  
Chromium Carbides ◽  
Steel Microstructure ◽  
The Matrix ◽  
Long Time ◽  
Secondary Precipitates ◽  
New Phase ◽  
18Cr Steel

The study presents the results of the identification of the phase composition of creep resistant cast austenitic 30Ni-18Cr steel with the addition of Ti and Nb after the annealing process conducted at 900°C for 10 and 500 hours. The microstructure of the as-cast steel showed mainly the presence of simple carbides. Depending on the alloy chemical composition, those were the TiC and NbC carbides. In the initial phase of annealing process, the nucleation of small secondary precipitates of chromium carbides Cr23C6 was observed to take place in cast steel microstructure at the matrix / simple carbides interface. After a long-time annealing, a new phase (G phase) was developing; the symbols of the phase were Ni16Ti6Si7 and Ni16Nb6Si7, respectively. The G phase was enclosing simple carbides forming with them the complexes of primary and secondary precipitates of a very intricate morphology. Chromium carbides Cr23C6 were also present there.

scholarly journals Explanation of the memory effect in argon

2005 ◽  
Vol 3 (2) ◽  
pp. 95-107 ◽  
Author(s):  
Vidosav Markovic ◽  
Sasa Gocic ◽  
Suzana Stamenkovic
Keyword(s):  
Time Delay ◽  
Memory Effect ◽  
Electrical Breakdown ◽  
Relaxation Times ◽  
Metastable States ◽  
Effective Lifetime ◽  
Breakdown Time ◽  
Long Time ◽  
Argon Ions ◽  
Phase Models

Memory effect - the long time variation of the electrical breakdown time delay on the relaxation time td (?) was observed in argon 24 hours after relaxation times and explained by the long-lived metastable states remaining from the preceding glow. However, the quenching processes reducing the effective lifetime of metastable states several orders of magnitude below that relevant for the time scale of observation were neglected. By applying approximate gas phase models it was found that the early afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular argon ions Ar2+ and the approximate value of their ambipolar diffusion coefficient is determined. After that, nitrogen atoms present as impurities and recombined on the cathode surface and/or field emission determine the breakdown time delay down to the cosmic rays and natural radioactivity level.

scholarly journals Covid-19 crisis

2020 ◽  
Vol 1 (1) ◽  
pp. 50-61
Author(s):  
Petra Kelecic
Keyword(s):  
Coming Out ◽  
Retail Banking ◽  
Distribution Model ◽  
Market Penetration ◽  
Key Factors ◽  
Distribution Models ◽  
Customer Expectations ◽  
Long Time ◽  
New Phase

The coronavirus situation is causing widespread concern and economic hardship for society, consumers and businesses worldwide. As for entire world, COVD-19 is the most serious challenge to financial institutions in long time. Banks are called upon to manage this new phase with urgency and aptness, to help deflect a worldwide recession. Until recently, majority of banks were focused on empowering both the psychical and digital distribution models. The “new normal” calls for reassessing of priorities and pushes new distribution model where psychical and digital are combined and act as one, with interconnected capabilities. This paper highlights importance of long-term positioning in post covid world, as market forces and customer behavior potentially change coming out of this crisis. In order to manage revenue and customer expectations, new customer-centric and digital based ecosystem should be established, leveraging on the latest technologies, aiming at increasing remote sales and market penetration. Having that in mind, article aims to shed light on key factors important for retail banking success in this “new future”.

Synthesis and Properties of Ytterbium Doped C60

1994 ◽  
Vol 349 ◽  
Author(s):  
Stephen H Irons ◽  
P. Klavins ◽  
J.Z. Liu ◽  
M.D. Lan ◽  
R.N. Shelton ◽  
...  
Keyword(s):  
High Temperatures ◽  
Magnetic Relaxation ◽  
Liquid Ammonia ◽  
Stoichiometric Composition ◽  
Amorphous Structure ◽  
Precise Control ◽  
Relaxation Effects ◽  
Magnetization Data ◽  
Long Time

ABSTRACTYtterbium doped C60 (YbxC60) has been synthesized through the use of a liquid ammonia intercalation route. This allows for precise control of the stoichiometric composition. Magnetization data were taken in fields up to 1 Tesla and temperatures between 5 and 300 K on samples with 1≤X≤5. We find the ytterbium introduces significant anisotropies into the system which give rise to long time magnetic relaxation effects that persist to high temperatures. We suggest the existence of an amorphous structure to explain the results.

The behaviour of the imaginary component of the AC magnetic susceptibility in disaccommodation experiments

1985 ◽  
Vol 46 (3) ◽  
pp. 350-358 ◽  
Author(s):  
M. Földeáki ◽  
G. Higelin ◽  
L. Köszegi ◽  
B. Schwendemann ◽  
F. Walz
Keyword(s):  
Magnetic Susceptibility ◽  
Imaginary Component ◽  
Ac Magnetic Susceptibility

AC MAGNETIC SUSCEPTIBILITY INVESTIGATION OF THE INTERGRAIN VORTEX PINNING INVOLVING Er IONS IN BULK (Bi1.6Pb0.4)(Sr1.8Ba0.2)(Ca1-xErx)2Cu3Oy SUPERCONDUCTOR

2000 ◽  
Vol 14 (12) ◽  
pp. 447-453 ◽  
Author(s):  
A. V. POP
Keyword(s):  
Volume Fraction ◽  
Ac Susceptibility ◽  
Field Amplitude ◽  
Vortex Pinning ◽  
Ac Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Bulk System ◽  
Flux Diffusion

Bulk superconducting samples with composition ( Bi 1.6 Pb 0.4)( Sr 1.8 Ba 0.2)( Ca 1-x Er x)2 Cu 3 O y (0 ≤ x ≤ 0.02 Er ) were prepared by conventional solid-state reaction. X-ray diffraction confirmed that with increasing Er concentration, the volume fraction of 2223 phase decreases. The intergranular vortex dynamics (and the effective pinning barrier) of the bulk system have been investigated by ac susceptibility as a function of temperature, frequency and ac field amplitude. The effect of Er ion on the intergrain vortex pinning was characterized quantitatively by using a flux diffusion model in which the effective pinning barrier depends nonlinearly on the current density.

ELECTRICAL AND MAGNETIC PROPERTIES IN Bi:2223 BULK DOPED WITH Cr

1999 ◽  
Vol 13 (15) ◽  
pp. 523-527 ◽  
Author(s):  
G. ILONCA ◽  
A. V. POP ◽  
I. G. DEAC ◽  
T. JURCUT ◽  
R. REDAC ◽  
...  
Keyword(s):  
Landau Theory ◽  
Ac Susceptibility ◽  
Transport Coefficients ◽  
Solid State Reaction Method ◽  
Time Dependent ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Electrical And Magnetic Properties ◽  
Separation Theory ◽  
Normal States

High-T c cuprates of "Bi-2223" bulk doped with Cr 0≤ x≤ 0.10 were prepared by the conventional solid state reaction method. The samples were investigated by electrical resistivity, Hall effect, Nernst effect, ac susceptibility and thermopower measurements in mixed and normal states. The transport coefficients depend strongly on the Cr contents in the samples. The temperature dependence nH(T) and inverse Hall mobility [Formula: see text] show an anomaly at a temperature around 240 K. These anomalies are discussed in the framework of phase separation theory. The experimental data in the mixed state are in agreement with the predictions of the time-dependent Ginsburg–Landau theory.

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