measurements are s h o w n in f i g 2 3 specific heat

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Unformatted text preview: region of pure stage I 1 to pure stage I c onversion as indicated by the X-ray data of Section 3 . 3 ( c). 5-5 ( e) S pecific Heat Comparison with Calculations b y S chick e t . al. ( 5 2 ) G iven the second order nature of the intercalate o rderd isorder transition t'he c alorimetric scans yield the variation in the specific heat near T area of the peak near T C C' T h e amplitude and/or c an thus be c o m p a r e d , at least q ualitatively, to calculations carried out by Schick et. a l . (52). T hey ( 5 2 ) c arried out a renormalization group calculation with a triangular Ising model to obtain the variation of C P n ear T C for adsorbed monolayers. Their calculated values were in excellent agreement ( 5 2 ) w ith measurements carried out o n grafoil substrates with submonolayer coverages of He atoms T h e specific heat of A g T iSZ n ear Tc has been 0 .40 Page -57aFigure 24 Contribution to the specific heat of A g T iSZ with respect to the sivler mole fraction 3 at room temperature. Cs- Cr X v s. 1 0 0.1 0.2 0.3 0.5 0.4 S ilver Mole F raction X C s = specific heat of AgyTiS, s ample Cr = specific heat of T S reference i, Page - 5 8 m easured and a c omparison w ith S c h i c k ' s theory ( 52) F i g . 2 5 s hows the measured variation o f Cp near T c and a r e p r o d u c t i o n of the r esrilts.calculatet1 b y Schick et. al. ( 52). T h e area under the experimental peak was determined to be 0 . 8 0 a nd this compares to the value of 0 . 8 5 a s estimated from the results of Schick e t . i ll. (52). T he agreement is perhaps fortuitous in that the measurements were carried o u t at approximately room temperature and thus there could be significant contributions to t h e specific heat f r o m other sources. T h e s e could include electronic and impurity contributions f o r example. Page -58aF igure 25 S pecific heat per p a r t i c l e versus T hesolid line temperature. r ep'resents t he measured values for A g0.qOTiS2. The dashed l i n e i s t he r e s u l t s calculated b y S chick e t . monolayer coverage al. (52) for a (taken from...
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