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Hydrostatic Pressure and Kinetic Phenomena in NaNbO 3 Single Crystals
Author(s) -
Pisarski M.
Publication year - 1980
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221010224
Subject(s) - polaron , hydrostatic pressure , seebeck coefficient , adiabatic process , condensed matter physics , kinetic energy , atmospheric temperature range , electrical resistivity and conductivity , activation energy , thermodynamics , materials science , thermoelectric effect , chemistry , physics , electron , quantum mechanics
Electrical conductivity σ, electric permeability Σ, and the Seebeck coefficient α in the 20°C < T < < 500 °C temperature range and in the 0 < p < 1 GPa pressure range are investigated. A strong linear dependence of these quantities on pressure for T < 360 °C and a shifting of the P ⇌ R phase transition temperature at a rate of dT a /dp = (120 ± 12) K/GPa are determined. From the linear dependences In σ(l/T) and In μ d (l/T) for various p = const, the activation energy is determined. The experimental relationship E a = E 0 — Bp is derived on the basis of the small‐polaron theory. Results related to transport phenomena are interpreted through the small‐polaron non‐adiabatic hopping theory. On the basis of the experimental and theoretical relations σ(T, p) = = σ 0 (T) (1 + C p ), and In μ b (T) the LO phonon energy ħω o , = 0.12 eV is determined, as well as the band half‐width J = 0.14 eV at normal pressure, and also the remaining small‐polaron parameters.