scholarly journals The principal magnetic susceptibilities of some paramagnetic crystals at low temperatures

Our knowledge of the temperature variation of the principal susceptibilities of paramagnetic crystals is as yet fragmentary. The principal susceptibilities of a number of paramagnetic crystals have been determined by Finke and by Rabi at room temperature but the first measurements on orientated crystals over any range of temperature were those of Foëx. He has published the principal susceptibilities of siderose (a mineral which is mainly ferrous carbonate but which contains appreciable quantities of the carbonates of manganese and other metals) over the range 87° to 400°K. and some measurements but not actual principal susceptibilities for manganese sulphate, MnSO 4 .4H 2 O. The writer measured the principal susceptibilities of cobalt ammonium sulphate and nickel sulphate, NiSO 4 . 7H 2 O over the temperature range 14°-290°K. and the writer and de Haas have published measurements on manganese ammonium sulphate crystals over the restricted range 14°-20° K. In addition Dupouy has repeated Foëx’s observations on siderose and has measured the principal susceptibilities of dialogite (a naturally occurring manganese carbonate) and oligist (Fe 2 O 3 ), all over a small range of temperature above 0° C. Quite recently Bartlett has employed Rabi’s method to determine the principal susceptibilities of the following compounds, CoSO 4 . 7H 2 O, CoSO 4 . (NH 4 ) 2 SO 4 . 6H 2 O, CoSO 4 . K 2 SO 4 . 6H 2 O, CuSO 4 . (NH 4 ) 2 SO 4 . 6H 2 O CuSO 4 . K 2 SO 4 . 6H 2 O, NiSO 4 . (NH 4 ) 2 SO 4 . 6H 2 O over the temperature range —45° to +55°C. In the writer’s opinion, however, Bartlett’s procedure is liable to several objections.

1975 ◽  
Vol 30 (3) ◽  
pp. 381-382 ◽  
Author(s):  
A. Abou- Zeid ◽  
G. Schneider

Various donor doping of ZnSb is investigated. Te-doping yields the most stable n-type crystals at room temperature; the samples show p-type behaviour at low temperatures. The influence of surface effects is demonstrated. It was possible to prepare n-type ZnSb for the whole temperature range.


2019 ◽  
Vol 7 (16) ◽  
pp. 9968-9976 ◽  
Author(s):  
Muhammad Rashad ◽  
Hongzhang Zhang ◽  
Xianfeng Li ◽  
Huamin Zhang

A Li3V2(PO4)3 based Mg2+/Li+ hybrid battery with excellent performance both at room temperature and low temperatures (0, −10, −20, −30, and −40 °C) is presented.


Although the investigation of the principal susceptibilities of paramagnetic crystals especially at low temperatures promises results of very great interest both from the theoretical and experimental standpoints, data on the subject are almost entirely wanting, probably at least in part as a result of the difficulty of making the necessary observations. Thus the only record of crystal susceptibilities as functions of the temperature is that of the measurement of the principal susceptibilities of siderose by Foëx, but these observations were not extended to lower temperatures than those obtainable with liquid air. The present preliminary note gives the results of an investigation of the principal susceptibilities of two crystals, namely, cobalt ammonium sulphate and nickel sulphate heptahydrate as functions of the temperature down to about 14° K. (melting point of hydrogen). These are thus the first observations of this type in the region of very low temperatures. The substances were chosen as representative of different classes of crystals (cobalt ammonium sulphate is monoclinic and nickel sulphate heptahydrate is rhombic), and as they promised results of special interest in the light of the phenomena shown by the mean susceptibilities obtained from measurements on the substances in powder form (see foregoing paper).


1935 ◽  
Vol 13b (3) ◽  
pp. 140-148 ◽  
Author(s):  
A. B. Van Cleave ◽  
O. Maass

The coefficients of viscosity of ammonia, propylene, ethylene and methyl ether, over the temperature range 23 to −80 °C., have been measured. A comparison is made between the present data and those of other authors for temperatures above 0 °C. It is estimated that the authors' results are correct to 0.2% and have a relative accuracy of 0.1%. It is claimed that they are the most accurate data for the viscosity of gases at low temperatures to date.The validity of a number of viscosity–temperature relations has been tested with the present data and those previously published (18, 20). In general, it is found that the equations of Sutherland and Jones hold at high temperatures but fail at low temperatures for substances such as carbon dioxide, sulphur dioxide, ammonia, methyl ether and propylene, which have viscosity–temperature curves that are convex to the temperature axis below room temperature. An empirical equation is suggested which adequately represents the variation of viscosity with temperature for these five gases over the temperature range 23 to −80 °C. However, this relation fails at high temperatures for all gases, and even at low temperatures for substances such as hydrogen, air and ethylene.It is pointed out that the viscosity–temperature curves for carbon dioxide, sulphur dioxide, ammonia, methyl ether and propylene each show a definite inversion or inflexion point. Below this inversion temperature the viscosity curves are convex to the temperature axis; above it they are concave to the temperature axis. In general, it seems that this inversion temperature bears a direct relation to the polarity of the molecule and to the critical temperature.


2005 ◽  
Vol 237-240 ◽  
pp. 402-407 ◽  
Author(s):  
Fanny Dyment ◽  
Silvia Balart ◽  
Constanza Lugo ◽  
Rodolfo A. Pérez ◽  
Nicolás Di Lalla ◽  
...  

The self-diffusion of Ru in the temperature range of (1267-1373) K and the Ru diffusion in pure aluminum in the temperature range of (632-873) K is reported. Difficulties were encountered when working with Ru as matrix (its brittleness at room temperature impeded a good sectioning) and they are the reason why only the order of magnitude of the self-diffusion in the small range of temperature studied is given. For Ru diffusion in aluminum, two experimental techniques were used: the conventional serial sectioning with use of a radiotracer, 103Ru, for the highest temperatures and Heavy Ions Rutherford Backscattering Spectrometry (HIRBS) for the lowest ones. The diffusion parameters are: Q = 199.4 kJ/mol and D0 = 4.1x10-2 m2/s. A comparison is made with Ru diffusion behavior in copper and silver.


2009 ◽  
Vol 23 (02) ◽  
pp. 265-273
Author(s):  
R. K. SINGHAL ◽  
D. R. SÁNCHEZ ◽  
ELISA SAITOVITCH ◽  
S. K. GAUR ◽  
K. B. GARG

Mössbauer spectroscopic measurements have been carried out for CeSn 3 and CeSn 3.1 single crystals in the temperature range 1.5 K to 300 K under applied magnetic field, with an aim to look into the local surroundings of the Sn site and the possibility of magnetization at low temperatures. The spectra indicate a paramagnetic ground state throughout the temperature range with two different doublets associated with two sites S1 and S2. This indicates two crystallographic sites of Sn with the presence of a distortion in the cubic crystal. However, the contribution of S2 site is very small (only 3% for the CeSn 3 but slightly higher, i.e., 4.3% for the CeSn 3.1) at room temperature. Upon cooling (below 4 K), the S2 contribution disappears for the stoichiometric sample ( CeSn 3) but continues to stay for the slightly nonstoichiometric compound ( CeSn 3.1). The isomer shift reveals a Sn 2+ valence state throughout. A weak hyperfine field has been observed only at low temperatures (4.2 and 1.5 K spectra) for both the compounds, but not for the 300 K spectra. This is indicative of some magnetization, i.e., an increase in magnetic moments of Ce atoms, that is felt by the neighbor Sn atoms through RKKY interactions. However, upon cooling the samples from 4.2 K to 1.5 K, no further enhancement in magnetization is observed. The magnetic field was also applied for the CeSn 3 sample at low temperatures to check if there is any enhancement in the magnetic properties that yielded negative results, i.e., the applied field is equal to the hyperfine field, indicating no enhancement of magnetic moment.


Author(s):  
Madhu Bochalya ◽  
Anand Nivedan ◽  
Sandeep Kumar ◽  
Arvind Singh ◽  
Sunil Kumar

We report broadband light emission (~350-800 nm) properties of two-dimensional layered (C12H25NH3)2MnCl4 inorganic-organic hybrid system in a large temperature range of ~5-400 K. At room temperature, the emission spectrum weighs...


Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.


2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.


1969 ◽  
Vol 11 (2) ◽  
pp. 189-205 ◽  
Author(s):  
E. A. Bruges ◽  
M. R. Gibson

Equations specifying the dynamic viscosity of compressed water and steam are presented. In the temperature range 0-100cC the location of the inversion locus (mu) is defined for the first time with some precision. The low pressure steam results are re-correlated and a higher inversion temperature is indicated than that previously accepted. From 100 to 600°C values of viscosity are derived up to 3·5 kilobar and between 600 and 1500°C up to 1 kilobar. All the original observations in the gaseous phase have been corrected to a consistent set of densities and deviation plots for all the new correlations are given. Although the equations give values within the tolerances of the International Skeleton Table it is clear that the range and tolerances of the latter could with some advantage be revised to give twice the existing temperature range and over 10 times the existing pressure range at low temperatures. A list of the observations used and their deviations from the correlating equations is available as a separate publication.


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