Polybis(4-azabenzimidazolato)-iron(II) and -cobalt(II). 3-D single diamond-like framework materials which exhibit spin canting and ferromagnetic ordering at low temperatures †

2000 ◽  
pp. 3931-3937 ◽  
Author(s):  
Steven J. Rettig ◽  
Victor Sánchez ◽  
Alan Storr ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Low Temperatures ◽  
Spin Canting ◽  
Framework Materials ◽  
Ferromagnetic Ordering

Transverse vibration driven large uniaxial negative and zero thermal expansion in boron bridged REPt3B framework materials

2018 ◽  
Vol 20 (21) ◽  
pp. 14876-14883 ◽  
Author(s):  
Sudipta Mondal ◽  
Chandan Mazumdar ◽  
R. Ranganathan
Keyword(s):  
Thermal Expansion ◽  
Rare Earth ◽  
Transverse Vibration ◽  
Low Temperatures ◽  
Linear Chain ◽  
Rare Earth Compounds ◽  
Thermal Expansion Behavior ◽  
Framework Materials ◽  
Expansion Behavior ◽  
Anomalous Thermal Expansion

REPt3B (RE = rare-earth) compounds exhibit anomalous thermal expansion behavior at low temperatures driven by transverse vibration of boron atoms perpendicular to the Pt(2)–B–Pt(2) linear chain.

Strategies towards the purposeful design of long-range ferromagnetic ordering due to spin canting

Polyhedron ◽  
2009 ◽  
Vol 28 (9-10) ◽  
pp. 1796-1801 ◽  
Author(s):  
Sebastian Thallmair ◽  
Wolfgang Bauer ◽  
Birgit Weber
Keyword(s):  
Long Range ◽  
Spin Canting ◽  
Ferromagnetic Ordering

Experimental Studies of Photoluminescence in Mn-Ion Implanted Silicon Rich Oxide Thin Film

2006 ◽  
Vol 910 ◽  
Author(s):  
Wei Pan ◽  
R.G. Dunn ◽  
M.S. Carroll ◽  
Y.Q. Wang
Keyword(s):  
Thin Film ◽  
Low Temperatures ◽  
Silicon Nanocrystals ◽  
Experimental Studies ◽  
Peak Temperature ◽  
Oxide Thin Film ◽  
Si Substrate ◽  
Doped Silicon ◽  
Ferromagnetic Ordering ◽  
Ion Implanted

AbstractIn this paper, we wish to report our preliminary experimental results from the photoluminescence (PL) studies in a Mn-ion implanted silicon-rich oxide (SRO) thin film. At 4 K, a broad PL peak, centered at ~ 1.2 eV, was observed. It is blue-shifted from the Si substrate peak at ~ 1.1 eV. The temperature (T) dependence of PL was carried out at zero magnetic (B) field and B = 0.5 Tesla, respectively, and showed quantitatively different behaviors. At B = 0, the PL intensity increases very slowly at low temperatures and reaches a maximal value at ~ 40 K. It then decreases as T is further increased. At B = 0.5 Tesla, the peak temperature (Tpeak), whether the intensity is maximal, moves to ~ 80-100 K, and the decreasing rate beyond Tpeak is much smaller than that at B = 0. We speculate that these two different behaviors might reveal, possibly, a ferromagnetic ordering in Mn-ion doped silicon nanocrystals.

scholarly journals Magnetic and Electric Studies of a New Cu(II) Perovskite-like Material

2004 ◽  
Vol 59 (1-2) ◽  
pp. 35-46 ◽  
Author(s):  
Mohga F. Mostafa ◽  
Ahmed A. A Youssef
Keyword(s):  
Magnetic Field ◽  
Thermal Analysis ◽  
Low Temperatures ◽  
Hopping Conduction ◽  
Thermally Activated ◽  
Universal Power Law ◽  
Initial Magnetic Susceptibility ◽  
Ferromagnetic Ordering ◽  
Type Conduction ◽  
Band Type

Thermal analysis of a lipid-like bilayer of [(CH2)9 (NH3)2]CuCl4 indicates one minor transition at 303 K and the following five major ones (with entropies in J/K-mole):The initial magnetic susceptibility at 320 Hz and a magnetic field of 160 A/m in the temperature range 75 - 290 K revealed a Curie-Weiss behavior of phase (V) and possible ferromagnetic ordering of phases (VI) and (IV) at low temperatures. The variation of the dielectric permittivity with temperature at 60.0 Hz - 100 kHz indicates large changes of the dipole moment at the transition temperatures. The conductivity is thermally activated and frequency dependent, following the universal power law: σ (ω) =σdc +A(T)ωs(T). Values of s being phase dependent. For phase (I), T > 383 K, band type conduction prevails. Hopping conduction is found in phases(II) and (III). Comparison with other Cuand Cd-containing materials is made. -PACS: 76, 77

Observation of Mn spin canting in PtFe alloys at low temperatures

1988 ◽  
Vol 18 (10) ◽  
pp. L237-L240 ◽  
Author(s):  
M Trhlik ◽  
B Sedlak ◽  
A L Erzinkyan ◽  
G M Gurevich ◽  
V P Parfenova ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Spin Canting

Equiatomic cerium intermetallics CeXX′ with two p elements

2015 ◽  
Vol 70 (10) ◽  
pp. 695-704 ◽  
Author(s):  
Rainer Pöttgen ◽  
Bernard Chevalier
Keyword(s):  
Solid Solutions ◽  
Low Temperatures ◽  
Simple Structure ◽  
Crystal Chemical ◽  
Structure Property ◽  
P Elements ◽  
Structure Property Relationships ◽  
Cerium Intermetallics ◽  
Ferromagnetic Ordering ◽  
Main Influence

AbstractThe equiatomic CeXX′ phases (X and X′ = elements of the 3rd, 4th, or 5th main group) extend the large series of CeTX intermetallics (T = electron-rich transition metal). These phases crystallize with simple structure types, i.e. ZrNiAl, TiNiSi, CeScSi, α-ThSi2, AlB2, and GdSi2. In contrast to the CeTX intermetallics one observes pronounced solid solutions for the CeXX′ phases. The main influence on the magnetic ground states results from the absence of d electrons. All known CeXX′ phases show exclusively trivalent cerium and antiferro- or ferromagnetic ordering at low temperatures. The crystal chemical details and some structure-property relationships are reviewed.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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