Electrical properties of La2−xSrxCoO4—II: Models and analysis of the relationship between cobalt 3d electron state and structural, electrical and magnetic properties

Polaronic Conduction in La2−Sr CoO4(0.25≤x≤1.10) below Room Temperature

“…To this end, the present work employs the La \V Sr V CoO system as an illustrative example because this system is in a homologous series with the K NiF structures (5)(6)(7)(8)(9) and there are no experiments on the electrical transports at rather low temperatures. The traditional interpretation based on the experiments at high temperatures (around 500 K) holds that the conduction is due to hopping processes of adiabatic small polarons (10)(11)(12). However, this interpretation requires more direct support.…”

“…As for the electrical transports, however, there are only a limited number of studies treating the conduction behavior at rather high temperatures (10)(11)(12)32). Le Coustumer et al (10) and Matsuura et al (11,12) interpreted their results in terms of hopping adiabatic small polarons.…”

“…As for the electrical transports, however, there are only a limited number of studies treating the conduction behavior at rather high temperatures (10)(11)(12)32). Le Coustumer et al (10) and Matsuura et al (11,12) interpreted their results in terms of hopping adiabatic small polarons. Matsuura et al suggested that the electronic structure of Co-3d levels split by the partial removal of the electronic degeneracy played an important role in the electronic transports in this system; their argument was based on a Mott-Hubbard insulator (11,12).…”

“…The crystallographic structures and magnetic properties of the La \V Sr V CoO system are well investigated (5,6,(9)(10)(11)(12)(26)(27)(28)(29)(30)(31)(32). As for the electrical transports, however, there are only a limited number of studies treating the conduction behavior at rather high temperatures (10)(11)(12)32).…”

Magnetic and transport properties of the layered perovskite systemSr2−yYyCoO4Wang1, Takayama‐Muromachi2 2005Phys. Rev. B8712811View full textAdd to dashboardCite

“…[10][11][12] It is well known that the dimensionality of a system is a key factor governing its electronic structure, and thus, twodimensional ͑2D͒ layered cobalt oxides are quite interesting to compare with the three-dimensional ͑3D͒ perovskites. Thus far, various studies have been carried out on K 2 NiF 4 -type cobalt oxides, [13][14][15][16][17][18][19][20] 4 according to their theoretical studies using the unrestricted Hartree-Fock approximation and the real-space recursion method. 19,20 In the present study, we have developed a K 2 NiF 4 -type cobalt oxide with only Co 4+ ions, Sr 2 CoO 4 , using a high pressure and high temperature technique.…”