Semiconducting Properties of Ln_2CuO_4 (Ln=Rare earths)

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概要

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• The temperature dependence of the resistivity and the thermoelectric power of Ln_2CuO_4 (Ln=rare earths) have been measured. The compounds of Gd, Sm, Nd, and Pr are semiconductive, while La_2CuO_4 Shows metallic conductivity. The tetragonal lattice of La_2CuO_4 Shrinks in the a axis and expands in the c axis compared to Pr_2CuO_4, in spite of the steady expansion of these lattice parameters for the compounds between Gd and Pr. The thermoelectric power of Ln_2CuO_4, but not La_2CuO_4, is negative, suggesting an electron-conducting or n-type semiconductor. The resistivity of the Ln_2CuO_4 at room temperature increases essentially with an increase in the atomic number of Ln. The plots of the thermoelectric power vs. the reciprocal temperature showed a steeper slope for the compounds of the heavier rare earths. The semiconductor-metal transition observed between La_2CuO_4 and Pr_2CuO_4 was explained in relation to the structural change (the shrinkage of the a axis and the expansion of the c axis) as being due to the change in the electron configurations of Cu^<2+>.

• 東北大学の論文

著者

• Yajima Seishi

  The Research Institute For Iron Steel And Other Metals

• KENJO Tadao

  The Research Institute for Iron, Steel and Other Metals

• Kenjo Tadao

  The Research Institute For Iron Steel And Other Metals

関連論文

• Siliconated Pyrolytic Graphite : Part 1. Preparation and Some Properties
• Field-Cooling Effect in the Amorphous Magnetic Oxide
• The Preparation and Crystal Structure of Ternary Rare Earth Borides, RCo_3B_2
• Siliconated Pyrolytic Graphite : Part 4. Electrical Resistivity
• Microstructure and Density of Pyrolytic Graphite
• Mechanism of the Pyrolytic Graphite Formation
• The Crystal Data of Ternary Rare Earth Borides, RCo_2B_2
• Neutron Irradiation Effects in Amorphous Pd-Si Alloy
• Magnetocrystalline Anisotropy of Y_(Co_Fe_y)_ Intermetallic Compounds
• Magnetocrystalline Anisotropy of Nonstoichiometric Y_Co_
• Preparation and Thermal Expansion of Pyrolytic Graphite-Bromine Residual Compounds
• The Electrical Anisotropies of Pyrolytic Graphite and Its Compounds
• Siliconated Pyrolytic Graphite : Part 2. The State of Silicon Present in Siliconated Pyrolytic Graphite
• Siliconated Pyrolytic Graphite : Part 3. Structural Features
• High Temperature Resistivity of Pyrolytic Graphite Bromine Residual Compounds
• Semiconducting Properties of Ln_2CuO_4 (Ln=Rare earths)
• Some Doping Effects on the Semiconducting Properties of Gd_2CuO_4
• The Crystal Structure and Nonstoichiometry of Rare Earth Oxyfluoride
• The Nonstoichiometry of Gadolinium Ditelluride
• The Crystal Data of Ternary Rare Earth Borides, RCo2B2
• The Crystal Structure and Nonstoichiometry of Rare Earth Oxyfluoride

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