Effect of deuteration on the electrical conductivity, dielectric constant ...

Volume 89A, number 1 PHYSICS LETIERS 19 April 1982
have given direct evidences regarding the phase transition
mechanisms in these crystals. Here the experimental
results from conductivity and dielectric measurements
conclusively show that DLAS undergoes
two phase transitions at _1.5° C and 191°C corresponding
to the two transitions in LAS occurring at 10° C
and 186.5°C. The transition at 10°C in LAS is a structural
one (accompanied by a unit cell doubling along
the a-direction) which has already been studied in detail
[6,7]. On the other hand no serious attempt has
so far been made in studying the mechanism involved
in the recently observed high temperature transition
in this crystal except that due to Syamaprasad and
Vallabhan, who suggested from electrical conductivity
and ionic thermo

Volume 89A, number 1 PHYSICS LETTERS 19 April 1982
[7) I.P. AJeksandrova,I.s. Kabanov, S.V. Melnikova, T.I.
OIekmasova and V.I. Yuzvak, KrystaUograf"Ja 22 (1977)
321.
(8) I.M.lskomev and I.N. Flyorov, Fiz. Tverd. Tela 19
(1977) 1040.
[91 V.I. YIIZVak, LI. Zerebstova, V.B. Shkuryaeva and I.P.
AJeksandrova, Kristallografla 19 (1974) 773.
[10) T.I. OIekmasova, I.S. Kabanov and V.I. Yuzvak, Phys.
Slat Sol. (a) 44 (1977) KISS.
Ill) T.I. Chekmasova and I.P. AJeksandroVl, Pbys. Stat. Sol.
(a) 49 (1978) KI8S.
fl21 U. Syamaprasad and C.P.G. ValIabhan, Solid State
Commun. 34 (1980) 899.
113) U. Syamaprasad and C.P.G. ValIabhan, Nat. Acad. Sci.
Lett (1nd1a) 3 (1980) 364.
(14) U. Syamaprasad and C.P.G. VaDabhan, to be published.
[IS] c. Ramuasby and Y. Syamasundara Rao, J. Phys. E12
(1979) 1023.
40
65
(16) U. Syamaprasad and C.P.G. VaDabhan, Solid State
Commun. 38 (1981) 555.
[17) U. Syamaprasad and C.P.G. VaIlabhan, PIoe. Nuclear
Phys. and Solid State Phys. Symp. I.I.T. (New Delhi)
Paper No. SLAI0 (1980).
[l8) U. Syamaprasad and C.P.G. Vallabhan, J. Phys. C14
(1981) L571.
(l9) U. Syamaprasad and C.P.G. VaDabhan, J. Phys. C14
(1981) L865.
(20) U. Syamaprasad and C.P.G. VaDabhan, Solid State
Commun., to be published.
[21 J YuzvaJc et al., Sov. Phys. CrystaDogr. 19 (1975) 480.
(22) B. Jayaram, Ph.D. Thesis, Indian Institute <strong>of</strong> Technology,
Madras (1982).
(23) D. Hadzi, Hydrogen bonding (peJgllJllon, New York,
1959).