An origin of good electrical conduction in La4BaCu5O13+δ

Abstract

We have prepared a set of polycrystalline samples of the metallic copper oxide La 4 BaCu 5Àx Co x O 13þd (0 x 0.35) and have measured the resistivity from 4 to 800 K. All the resistivities show metallic temperature dependence with a small magnitude less than 2 mX cm at 800 K, indicating that the metallic conduction is robust against impurities. The robust metallic conduction further suggests that this class of oxide is a promising candidate for electrical leads at high temperature, which might replace platinum. A detailed measurement and analysis on the Hall resistivity have revealed that at least two components are responsible for the electrical conduction, in which a large number of electrons of moderate mobility coexist with a much smaller number of holes of extremely high mobility. This large electron density well screens the impurity potential and retains the metallic conduction against 7% impurity doping. V C 2015 AIP Publishing LLC.

High Temperature Electrical Properties of Co-Substituted La4BaCu5O13+δ Thin Films Fabricated by Sputtering Method

“…Hence, the magnitude of α is determined by the balance between the conductivity and the Seebeck coefficient of each carrier. As Mori et al have pointed out that electrons are majority carriers, which is consistent with the negative Hall resistivity, they dominate the Hall measurement carrier density in LBCO [12]. On the other hand, considering that the fraction of the α e is as small as 4 µV/K at room temperature [10], the large positive Seebeck coefficient of the LBCO can be regarded as the contribution or concentration of holes.…”

“…However, there is no clear evidence of grain orientation, despite the lattice parameters of (121) for LBCO and (101) for SrTiO 3 being identical, which suggests that the grains of the deposited film were rather randomly oriented. The invariance of the c-axis length with Co-substitution has been reported in bulk [12]. No peak for Co 3 O 4 (PDF no.…”

“…The undoped and Ni-doped phases are metallic Pauli paramagnets; the Co-and Fe-doped materials show a metal-to-insulator transition with increasing the Ni(Co) content x and are weakly paramagnetic [11]. Mori et al reported that the LBCO bulk samples showed metallic temperature dependence with a low resistivity of less than 2 mΩcm at 800 K, indicating that the metallic conduction is robust against impurities of up to 7% Co-doping for the Cu site [12]. They discussed that the robust good metallic conduction is responsible for two components of the electron and hole conduction, and that the impurity potential seems to be screened by the high electron density.…”

Temperature dependence of electrical transport properties of La4BaCu5− xCoxO13+δ conducting oxide thin films

“…However, in the case of La 4 BaCu 5 O 13+δ , we cannot make use of these two experimental results because it is reported that the electrical carrier of this material is composed of both holes and electrons. 26) In the two-carrier model, the thermopower S is described by…”

“…The invariance of the c-axis length with Co-substitution has been reported in bulk. 26) The thickness of all films was about 150 nm.…”