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Hall Effect and Charge Carrier Generation in Y 1 Ba 2 Cu 3 O x
Author(s) -
Yoo HanIll,
Choi HyunSuk
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb05493.x
Subject(s) - tetragonal crystal system , orthorhombic crystal system , chemistry , hall effect , redox , charge carrier , analytical chemistry (journal) , oxygen , isothermal process , charge carrier density , electron mobility , crystal structure , electrical resistivity and conductivity , crystallography , materials science , thermodynamics , inorganic chemistry , doping , physics , optoelectronics , engineering , organic chemistry , chromatography , electrical engineering
The Hall coefficient, and hence the charge carrier density, of the system of Y 1 Ba 2 Cu 3 O x was measured at room temperature as a function of oxygen content, x , in its entire homogeneity range (6 < x < 7). The cuprate is essentially of the p‐type (σ p /σ n > 70) and of extrinsic origin for x > ∼6.37, below which the electron contribution grows appreciably, and hole generation mechanisms differ depending on crystal structure: one hole is generated for every oxygen atom added in the orthorhombic structure ( x > ∼6.5) and for every two oxygen atoms added in the tetragonal structure ( x < ∼6.5). The redox reactions, 1/2O 2 ( g ) = O i ′+ h . and O 2 ( g ) = (O i, O i )′+ h . , respectively, are proposed as responsible for the hole generation, and their equilibrium constants are evaluated with the reaction enthalpies of 0.75 ± 0.05 and 2.7 ± 0.2 eV, respectively. Based on these data, predictions about such properties as the oxygen potential dependences of isothermal conductivity are compared with reported results, and the numerical values for hole mobility are extracted. Other proposed redox reactions are discussed in light of the present findings.