scholarly journals Thermal Expansion of Fe2MnSi

1988 ◽  
Vol 41 (6) ◽  
pp. 781 ◽  
Author(s):  
JR Miles ◽  
TF Smith ◽  
TR Finlayson
Keyword(s):  
Thermal Expansion ◽  
Curie Temperature ◽  
Specific Heat ◽  
Grüneisen Parameter ◽  
Specific Heat Data ◽  
Thermal Expansion Data ◽  
Narrow Peak ◽  
Temperature Range ◽  
Weak Anomaly ◽  
Heat Data

Measurements of the thermal expansion of FezMnSi in the temperature range 200-300 K are reported. A large, relatively narrow peak is found at the magnetic re-ordering temperature in contrast to a broad, weak anomaly at the Curie temperature. Values for the magnetic Gruneisen parameter 'Y m are derived from the thermal expansion data and previously reported specific heat data following the subtraction of a non-magnetic background.

Microwave absorption by ortho-H2 pairs in solid hydrogen: temperature and density dependence of the frequencies

1980 ◽  
Vol 58 (9) ◽  
pp. 1356-1359 ◽  
Author(s):  
R. Jochemsen ◽  
B. W. Statt ◽  
W. N. Hardy
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Density Dependence ◽  
Energy Levels ◽  
Electric Quadrupole ◽  
Experimental Result ◽  
Para Hydrogen ◽  
Specific Heat Data ◽  
Helium Gas ◽  
Heat Data

The energy levels of an ortho-hydrogen pair in solid para-hydrogen are mainly determined by the electric quadrupole–quadrupole interaction between the ortho molecules which has an R−5 dependence. The frequencies of the observed absorption lines should therefore shift as a function of temperature due to thermal expansion. The experimental result for this shift, however, is a factor of 2 to 3 larger than that expected from thermal expansion calculated from specific heat data. We have also pressurized the sample at constant temperature with helium gas up to ≈0.4 bar, and obtained a confirmation of the R−5 dependence.

Thermodynamic Properties of Natural Rubber and Isoprene

1966 ◽  
Vol 39 (1) ◽  
pp. 143-148 ◽  
Author(s):  
R. W. Warfield ◽  
M. C. Petree
Keyword(s):  
Free Energy ◽  
Glass Transition ◽  
Thermodynamic Properties ◽  
Natural Rubber ◽  
Specific Heat ◽  
Gibbs Free Energy ◽  
Kcal Mole ◽  
Specific Heat Data ◽  
Temperature Range ◽  
Heat Data

Abstract Using published specific heat data, the entropy, enthalpy, and Gibbs free energy of natural rubber (NR) have been calculated over the temperature range 0 to 320° K. The thermodynamic function Cp/T as a function of T calculated for NR exhibits a maximum at 50° K and another maximum at 210° K, which is associated with the glass transition. The number of classically vibrating units per repeating unit of NR is 6.61 at 300° K. These functions have also been calculated for isoprene over the temperature range 0 to 300° K. At 298.16° K the entropy of polymerization was found to be 24.00 cal mole−1deg−1 and the free energy of polymerization − 10.7 kcal/mole.

Specific heat data of high-Tc superconductors: Lattice and electronic contributions

1989 ◽  
Vol 69 (6) ◽  
pp. 625-629 ◽  
Author(s):  
J.E. Gordon ◽  
M.L. Tan ◽  
R.A. Fisher ◽  
N.E. Phillips
Keyword(s):  
Specific Heat ◽  
High Tc Superconductors ◽  
Specific Heat Data ◽  
High Tc ◽  
Heat Data

THE COMBINED ANALYSIS OF SPECIFIC HEAT AND THERMAL EXPANSION OF Nd1−xLuxMn2 COMPOUNDS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 810-813
Author(s):  
N.H. KIM-NGAN ◽  
P.E. BROMMER ◽  
J.J.M. FRANSE
Keyword(s):  
Magnetic Properties ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Crystal Field ◽  
Spin Fluctuation ◽  
Spin Reorientation ◽  
Antiferromagnetic Order ◽  
Combined Analysis ◽  
Temperature Range

Specific heat and thermal expansion measurements have been performed on Nd1−xLUxMn2 in the temperature range between 1.5K and 300K. Below 10K, anomalies are observed which are ascribed to a spin reorientation of the Nd sublattice. These anomalies are only slightly affected by the substitution of Nd by Lu. Large effects, however, are observed on the magnetic properties of the Mn sublattice. The antiferromagnetic order disappears for x exceeding 0.30. The data are analysed in terms of Grüneisen parameters. In the paramagnetic compound LuMn2, a spin-fluctuation contribution to the thermodynamic properties is observed. In the Nd-containing compounds, distinct contributions from the crystal field acting on the Nd ions can be distinguished. The variation of the magnetic properties of the Mn sublattice with the concentration of Lu is discussed.

Thermal Expansion

1983 ◽  
pp. 75-132
Author(s):  
A. F. Clark
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Specific Heat ◽  
Measurement Techniques ◽  
Short Discussion ◽  
Thermal Expansion Data ◽  
Novel Materials ◽  
Advantages And Disadvantages ◽  
Expansion Theory ◽  
Methods Of Measurement

Abstract Specific heat and thermal expansion are closely related. Following a discussion on thermal expansion theory, methods of measurement techniques are presented along with their advantages and disadvantages. The results of the measurements are then summarized for three classes of materials: metallics, nonmetallics, and composites. Because predicting thermal expansion values for unmeasured or novel materials is useful, the chapter also describes the means of making educated guesses for low-temperature values. A short discussion on how thermal expansion data can be used is followed by a section describing where such data can be found.

The Effect of Thermal History on Porcelain Expansion Behavior

1989 ◽  
Vol 68 (9) ◽  
pp. 1313-1315 ◽  
Author(s):  
C.W. Fairhurst ◽  
D.T. Hashinger ◽  
S.W. Twiggs
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Heating Rate ◽  
Room Temperature ◽  
Heating Rates ◽  
Thermal Expansion Data ◽  
Temperature Range ◽  
Expansion Behavior

Porcelain-fused-to-metal restorations are fired several hundred degrees above the glass-transition temperature and cooled rapidly through the glass-transition temperature range. Thermal expansion data from room temperature to above the glass-transition temperature range are important for the thermal expansion of the porcelain to be matched to the alloy. The effect of heating rate during measurement of thermal expansion was determined for NBS SRM 710 glass and four commercial opaque and body porcelain products. Thermal expansion data were obtained at heating rates of from 3 to 30°C/min after the porcelain was cooled at the same rate. By use of the Moynihan equation (where Tg systematically increases in temperature with an increase in cooling/heating rate), the glass-transition temperatures (Tg) derived from these data were shown to be related to the heating rate.

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