Relationship between the Spontaneous Magnetization, Spontaneous Magnetostriction and Heat Capacity in the Compound Mn5Ge3

2010 ◽  
Vol 168-169 ◽  
pp. 153-156
Author(s):  
S.M. Podgonykh ◽  
K.E. Bolotin
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion ◽  
Curie Temperature ◽  
Thermal Expansion Coefficient ◽  
Spontaneous Magnetization ◽  
Magnetic Part ◽  
Spontaneous Magnetostriction ◽  
Magnetostrictive Deformation ◽  
Curie Temperature Tc ◽  
Volume Thermal Expansion Coefficient

Spontaneous magnetization Ms of the ferromagnetic compound Mn5Ge3 with the Curie temperature TC=305 K has been studied in the temperature range from 2 to 400 K. The relationships between the magnetic part of the heat capacity (CMAG), the magnetic part of the volume thermal expansion coefficient (TEC) MAG, and the Ms for the compound Mn5Ge3 have been considered. It has been found that the magnetic part of the heat capacity can be well approximated by the dependence CMAG(T)=a×|dMs2/dT|–b×|dMs4/dT| with a>0 and b>0, and the magnetic part of the TEC, by the dependence  MAG=C1×dMs2/dT+C2×dMs4/dT with C1<0 and C2>0 in the whole temperature. It is assumed that the main sources in the formation of the observed CMAG(T) and MAG(T) dependences are the changes in the elastic, magnetoelastic, magnetovolume, and magnetostatic energies of the sample that appear as a result of the spontaneous magnetostrictive deformation with temperature changing.

Anomalous Thermal Expansion and Spontaneous Magnetostriction of Gd2Fe16.5Cr0.5 Compound

2012 ◽  
Vol 580 ◽  
pp. 544-547
Author(s):  
Chun Jing Gao ◽  
Yan Ming Hao ◽  
Fei Fei Liang ◽  
Huai Gu Hu
Keyword(s):  
Magnetic Properties ◽  
Thermal Expansion ◽  
Curie Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Magnetic State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spontaneous Magnetostriction ◽  
Anomalous Thermal Expansion

The thermal expansion and magnetic properties of Gd2Fe16.5Cr0.5compound have been investigated by means of X-ray diffraction and magnetization measurements. The Gd2Fe16.5Cr0.5compound has a rhombohedral Th2Zn17-type structure. The Curie temperature of Gd2Fe16.5Cr0.5compound is about 560K. This value is about 50K higher than that value of the mother compound Gd2Fe17. A small average thermal expansion coefficient, = 1.65×10-6/K, and a negative average thermal expansion coefficient, = -1.46×10-5/K, were found in Gd2Fe16.5Cr0.5compound by X-ray diffraction in the temperature range 294 - 514K, and 514-613K, respectively. There exists anisotropic strong spontaneous magnetostriction in the magnetic state of Gd2Fe16.5Cr0.5compound.

scholarly journals Thermal Properties of Stabilized Zirconia at Low Temperatures

1985 ◽  
Vol 38 (4) ◽  
pp. 617 ◽  
Author(s):  
JG Collins ◽  
SJ Collocott ◽  
GK White
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Low Temperatures ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Stabilized Zirconia ◽  
Elastic Data

The linear thermal expansion coefficient a from 2 to 100 K and heat capacity per gram cp from 0�3 to 30 K are reported for fully-stabilized zirconia containing a nominal 16 wt.% (9 mol.%) of yttria. The heat capacity below 7 K has been analysed into a linear (tunnelling?) term, a Schottky term centred at 1�2 K, a Debye term (e~ = 540 K), and a small T5 contribution. The expansion coefficient is roughly proportional to T from 5 to 20 K and gives a limiting lattice Griineisen parameter 'Yo ::::: 5, which agrees with that calculated from elastic data.

scholarly journals Колебательные и тепловые свойства оксианионных кристаллов

2018 ◽  
Vol 60 (3) ◽  
pp. 565
Author(s):  
Д.В. Корабельников
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Density Functional ◽  
Functional Theory ◽  
Atomic Orbitals ◽  
Thermodynamic Potentials ◽  
Intramolecular Vibrations ◽  
Ir And Raman

AbstractThe vibrational and thermal properties of dolomite and alkali chlorates and perchlorates were studied in the gradient approximation of density functional theory using the method of a linear combination of atomic orbitals (LCAO). Long-wave vibration frequencies, IR and Raman spectra, and mode Gruneisen parameters were calculated. Equation-of-state parameters, thermodynamic potentials, entropy, heat capacity, and thermal expansion coefficient were also determined. The thermal expansion coefficient of dolomite was established to be much lower than for chlorates and perchlorates. The temperature dependence of the heat capacity at T > 200 K was shown to be generally governed by intramolecular vibrations.

Negative Thermal Expansion of Gd2Fe16.5Cr0.5 Compound with Th2Ni17-Type Structure

2011 ◽  
Vol 299-300 ◽  
pp. 47-50
Author(s):  
Yan Ming Hao ◽  
Fei Fei Liang ◽  
Xiao Hong He ◽  
Wu Yan Zhao ◽  
Yue Ting Qin ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Curie Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Temperature Range

The thermal expansion and the Curie temperature of Gd2Fe16.5Cr0.5 compound have been investigated by means of x-ray diffraction and magnetization measurements. The result shows that the Gd2Fe16.5Cr0.5 compound annealed at 1243°C has a hexagonal Th2Ni17-type structure. Cr atom substituting for Fe atom can increase the Curie temperature obviously. In magnetic state, an anisotropic anomolous thermal expansion was observed. Along the c-axis, the average linear thermal expansion coefficient αc=-2.79×10-6/K in the temperature range 294-472K, and αc =-3.09×10-5/K in 472-592K. Along the a-axis, the average linear thermal expansion coefficient αa =9.22×10-6/K in 294-552K, and αa =-1.41×10-5/K in 552-592K. In the temperature range 472-592K, the average volume thermal expansion coefficient αv =-2.14×10-5/K. The mechanism of the thermal expansion anomaly of Gd2Fe16.5Cr0.5 compound was discussed in this paper.

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