Magnetic phase diagram and transport properties of the mixed-valence manganites

In this article, we investigate the magnetic phase diagram and the transpor t properties of the mixed-valence manganites using a Hamiltonian which incl udes a finite Hund's rule coupling strength and the dynamic Jahn-Teller eff ects. We find that the doping dependence of the Curie temperature has a max imum at x = 0.3-0.5. It is also shown that the resistivity at the high temp erature range exhibits a semiconducting behavior which decreases with press ure. Our results are qualitatively in agreement with the experiments. (C) 1 999 Elsevier Science Ltd. All rights reserved.