Chromium Debye temperature

Clearly one obtains the best performance for a given time constant with a detector that has the lowest possible heat capacity. The heat capacity of a crystal varies like C oc (T/0 )3, where On is the Debye temperature. Diamond has the highest Debye temperature of any crystal, so FIRAS used an 8 mm diameter, 25 fim thick disk of diamond as a bolometer (Mather et al., 1993). Diamond is transparent, so a very thin layer of gold was applied to give a surface resistance close to the 377 ohms/square impedance of free space. On the back side of the diamond layer an impedance of 267 ohms/square gives a broadband absorbtion. Chromium was alloyed with the gold to stabilize the layer. The temperature of the bolometer was measured with a small silicon resistance thermometer. Running at T = 1.6 K, the FIRAS bolometers achieved an optical NEP of about 10 14 W/y/IIz. 

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... 

The low temperature specific heat of ten ternary alloys with 3 at.% of Si have been investigated by [ 1977Si], the chromium content ranging from 0.049 to 0.97 at%. The Debye temperature was obtained by interpolation between the two limits of the soUd solution. 

Determine the specific heat of chromium at the normal boiling temperature of liquid hydrogen by use of the Debye function. 

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