Electronic specific-heat coefficient

It is a matter of speculation as to whether or not the activity would pass through a significant maximum at a surface composition between 0 and 30% Rh. It is interesting to note in this connection that the magnetic susceptibility (156, 157) and the electronic specific heat coefficient (156) increase from low values at 60% Ag-Pd through pure palladium and reach a maximum at - 5% Rh-Pd, thereafter decreasing smoothly to pure rhodium. Activity maxima have also been reported for reduced mixed oxides and supported alloys of group VIII metal pairs. For example, in the... 

Fig. 1. Cg/T versus T for NpSn3 where Ce is the electronic specific heat. The solid curve is the mean-field theoretical prediction. The electronic specific heat coefficients of the paramagnetic and ordered states are designated by Vpa, = 242 andVoni = 88 mJ/(mol K ), respectively. (Trainor et al. )...

Many light actinide alloys which are not magnetic have a T dependence of the resistivity at low temperature as well as a large electronic specific heat coefficient y (Table 4). However, the archetype of a spin fluctuation system is UAI2. The electrical resistivity is proportional to T with a very large coefficient a = 0.15 qQcm/K up to 5... 

R,R rare earth metal Y electronic specific heat coefficient... 

Electronic structures of GICs, thus theoretically characterized, are investigated experimentally by means of various techniques, such as x-ray photoemission spectra, ultraviolet photoelectron spectra, electron energy loss spectra, magneto-oscillation, optical reflectance, Raman spectra, Pauli paramagnetic susceptibility, electronic specific heat coefficient, NMR, positron annihilation, etc. Comparisons between theoretical treatments and experimental characterizations will be discussed in the Sections 6.3.2 and 6.3.3 of this chapter for actual GICs. 

Comparison of the magnetic properties of Sc3In and ZrZn2. The parameters pTM and peff are the moments per transition metal atom deduced from magnetization and susceptibility measurements respectively y the electronic specific heat coefficient, 0n the Debye temperature, 0p the paramagnetic Weiss temperature, and AS the entropy change at Tc. The ratio qc/qs is the Rhodes-Wohlfarth ratio. 

Magnetic properties of Zr(Fe1 xCo t)2. a is the volume saturation magnetization, Tc the Curie temperature, 8p the paramagnetic Curie temperature, C the Curie constant, y the electronic specific heat coefficient, //hyp the hyperfine field, and us the spontaneous magnetostriction coefficient. 

Fig. 32. Calculated values of the electronic specific heat coefficient (dotted line) and experimental values...

This compound has the same structure as Au4Mn and Au4V (q.v.). Resistivity measurements (Toth et al. 1969) give a Curie temperature of 200 K and the electronic specific heat coefficient y is 4.5 mJ (mol K)-1. 

Binary phases. Specific heat measurements of ThPt between 1.5 and 40 K performed by Luengo et al. (1976) indicate no transition. The material is probably paramagnetic down to 1.5 K. Also the temperature dependence of the electrical resistivity measured by the same authors up to 300 K, shown in the inset of fig. 3.1, is regularly linear with no anomaly. The electronic specific heat coefficient y = 3.5 mJ/mol K2 indicates that 5f states (and also 5d states) are absent at Ev. 

Fig. 3.24. Concentration dependence of the Neel temperature ( ), low-temperature limit of the magnetic susceptibility x(0) ( ) and low-temperature electronic specific heat coefficient y (a) in...

The coefficient of variability of the resulting fit was 0.7%. Usually A is zero, and a plot of C/T vs. is linear with intercept y (the electronic specific heat coefficient) and slope j8. A Debye temperature, do, can be extracted from the latter quantity using the numerical relationship... 

The specific heat of chromium rich Cr-Ni and Cr-Fe-Mo alloys was measured by [1971Bau] in the temperature range 1.3-4.2 K. Measurements were made for compositions of 20 mass% Mo and 0-20 mass% Fe. This experimental program was intended primarily for the determination of the electronic band stmcture of 3d transition elements. It is known that Cr-Fe alloys exhibit unusual electron specific heat coefficients and an abnormally low Debye temperature, which is attributed to a complex magnetic stmcture of these alloys. The addition of 20 at.% Mo may avoid such complications, as the alloy becomes paramagnetic at liquid He temperatures. The results of the measurements are shown in Table 4. The temperature dependence of the specific heat is expressed as C = 234 R (770) + where R is the gas constant and 0 is the apparent Debye temperature. The authors concluded that the values of the specific heat coefficients and the Debye temperature are rather unusual (a low value of the apparent Debye temperature). They cannot be caused by... 

Electronic specific heat coefficients y [mJ/K mol] for various Ybr-Y compounds... 

Colclough (1986) (0.016-0.81 K) derived values for the electronic specific heat coefficient (y) and the magnetic contribution to the heat capacity. In combination with the nuclear contribution as derived in Part 8.11, the heat capacity up to 1 K can be represented by... 

CeAuln orders antiferromagnetically at 5.7 K as is evident from magnetic susceptibility and specific heat data (Pleger et al., 1987). The electronic specific heat coefficient y is 30 mJ/molK. The temperature dependence of the electrical resistivity of CeAuln shows a magnetic scattering contribution. Thermal conductivity measurements show values of 50 and 60 mW/cmK for LaAuIn and CeAuln, respectively. 

Estimated unenhanced electronic specific heat coefficient (mJ/mole-K and low temperature Debye temperature i,(0) (K) for selected rare earth metals where... 

The Debye temperature of La is anomalously low, as first noticed by Kasuya (1966). Table 10.1 shows the Debye temperatures and electronic specific heat coefficients for La, Lu, Y and Sc. The Debye temperature of d-hep La is 152 K in comparison to 205 K for Lu. Strictly speaking, the data cannot be compared so simply. The Debye temperature of La will increase under a pressure of 100 kbar, which should be applied in a Gedanken-experiment to correct for the lanthanide contraction. The corresponding volume compression is 24% (Syassen and Holzapfel, 1975). For an estimate of an upper bound we use the largest... 

Debye temperature 0 (0) and electronic specific heat coefficient y for the trivalent rare earths Sc, Y, Lu and La. Error limits are those given in the original papers. 

As seen from table 10.1, the electronic specific heat of both phases of La is larger than that of Lu. However, no conclusion can be drawn as to a higher density of states in La. The electronic specific heat coefficient y is proportional to the density of states times the electron-phonon enhancement factor... 

Fig. 10.20. T, electronic specific heat coefficient y and Debye temperature d as a function of concentration x in the alloy system Lai jYj (Satoh and Ohtsuka, 1%7).

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