Specific Heat of Amorphous and Crystalline PbTiO_3 at Low Temperatures

概要

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Specific heat data are reported, 1.7-30 K, on four samples of PbTi0. : am-orphous ribbon ( - 20 vm thick) ; crystallized ribbon ( - l zna grain size) ; cry-stalline powder ( - l /7111 grain size) ; and ceramic; pellet ( - 2 prn grain size).Both the amorphous and crystallized ribbon samples display strong Schottkybehavior below 4 K with nearly identical (two level) energy separations : 78 mK.Pb0 loss from the thin ribbons is postulated to explain these cffects. Below 3 K,the powder and pellet samples display a glasslike linear term in the specific heat,and the coefficients of these terms (1.4 x 10 ' J cm "K ') are the same magnitudeas those found in glasses. All crystalline forms of PbTi0. clisplay maxima inCAT' at 15 K, and these maxima are accurately represented by single Einsteinterms with frequencies 47-52 cm '. Amorphous PbTi0. displays a CAT' maxi-mum at 10 K, as does vitreous Sin.. A Debye temp?erature for crystalline PbTi0.of 337 K is reported; the effective Debye temperature for amorphous PbTi03is found to be 256 K.
社団法人日本物理学会の論文
1983-01-15