Phase coexistence and resistivity near the ferromagnetic transition of manganites.
Pairing of oxygen holes into heavy bipolarons in the paramagnetic phase and their magnetic pair breaking in the ferromagnetic phase (the so-called current-carrier density collapse) has accounted for the first-order ferromagnetic-phase transition, colossal magnetoresistance, isotope effect, and pseudogap in doped manganites. Here we propose an explanation of the phase coexistence and describe the magnetization and resistivity of manganites near the ferromagnetic transition in the framework of the current-carrier density collapse. The present quantitative description of resistivity is obtained without any fitting parameters, by using the experimental resistivities far away from the transition and the experimental magnetization, and is essentially model-independent.
Alexandrov
A S
AS
Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom.
Bratkovsky
A M
AM
Kabanov
V V
VV