ON THE THERMAL EXPANSION OF MgB2 AT NORMAL STATE

2007 ◽  
Vol 21 (01) ◽  
pp. 133-143 ◽  
Author(s):  
J. MEENA DEVI ◽  
K. RAMACHANDRAN
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Specific Heat ◽  
Normal State ◽  
Temperature Measurements ◽  
Electronic Contribution ◽  
Superconducting Transition ◽  
Temperature Range ◽  
Lattice Specific Heat

Thermal expansion of MgB 2 at normal state is measured experimentally in the temperature range 300–400 K. Lattice and electronic contribution to the thermal expansion is determined from the Gruneisen relation using electronic and lattice specific heat. This is compared with the low temperature measurements for predicting superconducting transition.

Specific heat of ordered equiatomic InMg, CuPt, and CuAu I below 30 K

1980 ◽  
Vol 58 (2) ◽  
pp. 164-167 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Specific Heat ◽  
Debye Temperature ◽  
Normal State ◽  
Pure Gold ◽  
Two Dimensional ◽  
Superconducting Transition ◽  
Dimensional Effect ◽  
Lattice Specific Heat ◽  
Increasing Temperature

The results of specific heat measurements on ordered In −51.67 at.% Mg are presented. A superconducting transition was seen at about 0.95 K. In the normal state, the lattice specific heat varies in the usual way with temperature, i.e., the Debye temperature initially decreases with increasing temperature. This behavior was also seen in ordered equiatomic CuPt but in ordered equiatomic CuAu I the Debye temperature first goes through a maximum before decreasing to the usual minimum. The structure of all three alloys consists of alternating layers of different mass and it was initially supposed that the CuAu I result was a two-dimensional effect. However, the more recent and normal results on InMg and CuPt make this improbable and it appears that the CuAu I result is related to the behavior of pure gold which is itself anomalous.

Thermal Expansion And Grüneisen Parameters Of Quasicrystals

1998 ◽  
Vol 553 ◽  
Author(s):  
K. Edagawa ◽  
K. Kajiyama ◽  
S. Takeuchi
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Elastic Moduli ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
X Ray ◽  
Temperature Range ◽  
Lattice Specific Heat ◽  
Two Phases ◽  
Phonon Properties

AbstractTo investigate anharmonic phonon properties, thermal expansion measurements have been performed for icosahedral (i-) Al-Pd-Mn and decagonal (d-) Al-Cu-Co quasicrystals by X-ray diffractometry in the temperature range between 100 and 800K. The linear thermal expansion coefficient α(T) of i-Al-Pd-Mn is 1.1 × 10−5K−1 at 300K, which is about a half of that of pure Al phase. The measured α(T) of d-Al-Cu-Co coincides almost completely with that of i-Al-Pd- Mn and no appreciable anisotropy was detected between the tenfold periodic direction and a quasiperiodic direction perpendicular to it. The Grfneisen parameter γ(T), has been evaluated from the measured α(T) using the data of lattice specific heat and elastic moduli previously reported. The γ(T) values for the two phases are comparable to those for conventional metallic crystals and almost constant over the temperature range studied.

scholarly journals THERMAL EXPANSION STUDY OF A UVAROVITE RICH GARNET

2007 ◽  
Vol 21 (11) ◽  
pp. 1915-1922 ◽  
Author(s):  
G. PARTHASARTHY ◽  
R. SRINIVASAN ◽  
G. D. MUKHERJEE ◽  
C. BANSAL ◽  
ASHOK CHATTERJEE
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Thermodynamic Parameters ◽  
Semiclassical Model ◽  
Lattice Specific Heat ◽  
First Time ◽  
Thermal Expansion Study

Thermal expansion measurements have been performed on a uvarovite rich garnet sample for the first time and compared with the expansion data on grossular and pyrope-rich garnets reported in the literature. A semiclassical model has been used to analyze the data and to obtain various thermodynamic parameters. Using these parameters, the lattice specific heat and the corresponding entropy have also been calculated.

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.

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