Specific heat coefficient

The component specific heat capacity coefficients, A, B, C, D, are stored as a matrix. If an energy balance is to be made on several units, the specific heat coefficients for all the components can be entered at the start, and the program rerun for each unit. 

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... 

We now give a simple application of the present method to Plutonium which is a good test case. Pu lies between light actinides with itinerant 5/ electrons and heavy actinides with localized 5/ electrons. The competition between these two electronic regimes in Pu is responsible for a lot of unusual properties as large values of the linear term in the specific heat coefficient and of the electrical resistivity or a very complex phase diagram. 

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

Not only the specific heat coefficient, y, takes such a large value, also the coefficient of the quadratic term in the temperature dependence of the resistivity is anomalously large ... 

Figure 1. The effect of strong electron correlations on the low-temperature specific heat coefficient y.

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. 

For applications, see Refs. [84-89]. Reference [89] describes the results of relativistic band structure calculations for CeRu2Si2, and also in this case it was found that the topology of the Fermi surface is well described by the LDA, although the T-linear specific heat coefficient is very large, 7 350 mJ/molK. This, and the similar observation made for UPts were explained [85,86] by showing that the Fermi surface topologies derived from renormalized bands and an LDA calculation for this kind of systems... 

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. 

When An is small (well below the Hill limit) and the corresponding 5f-5f overlap is large and/or when the 5f-ligand hybridization is strong, one expects that a relatively broad 5f band is formed, intersected by EF. A relatively low density of the 5f states at EF is reflected in a modest value of the specific heat coefficient y. The magnetic susceptibility x is practically temperature independent, but the values can be somewhat enhanced with respect to the specific heat data if the formula... 

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...

AnX5 compounds. Structure parameters and values of linear specific heat coefficient 7,... 

AnBe13 compounds. Lattice parameter a type of the ground state (WP denotes a weak paramagnet, S a superconductor, AF an antiferromagnet) and the low-temperature specific heat coefficient y. 

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... 

Low-Temperature Specific Heat. Although no liquid-helium-temperature data exist for boron, the specific heat has been measured between 13 and 305 K by Johnston et al [ ]. As a result, a Debye temperature of 1219 K has been assigned to the temperature range of 60 to 150 K [ ]. This value is assumed to be applicable at low temperatures and is used in synthesizing a value for the lattice specific heat coefficient ( 3 or jS) of the boron/aluminum composite, on the assumption that the mixture principle is applicable, viz. ... 

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... 

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