Peculiarities in low temperature properties of doped manganites A_1-xB_xMnO₃

Abstract:

The phase diagram and low temperature properties of the doped manganites A_1-xB_xMnO₃ are discussed for the concentrations $x \le 0.4$. The transition from insulating antiferromagnetic to metallic ferromagnetic state at ${x_{cr}} \simeq 0.16$ is treated by means of percolation theory. The unifying description of insulating and metallic states is presented. The undoped manganite is a band insulator consisting of ferromagnetic layers, which are coupled antiferromagnetically along the c direction with a low Néel temperature. The metallic phase can be described by the two-band Fermi liquid picture. The behavior of conductivity, spin wave excitations, etc. is analyzed and the comparison with experimental data is carried out.