Magnetic phase diagram of the anisotropic double-exchange model: A Monte Carlo study

The magnetic phase diagram of highly anisotropic double-exchange model syst ems is investigated as a function of the ratio of the anisotropic hopping i ntegrals, i.e., t(c)/t(ab), on a three-dimensional lattice by using Monte C arlo calculations. The magnetic domain structure at low temperature is foun d to be a generic property of the strong anisotropy region. Moreover, the t (c)/t(ab) ratio is crucial in determining the anisotropic charge transport due to the relative spin orientation of the magnetic domains. As a result, we show the anisotropic hopping integral is the most likely cause of the ma gnetic domain structure. It is noted that the competition between the reduc ed interlayer double-exchange coupling and the thermal frustration of the o rdered two-dimensional ferromagnetic layer seems to be crucial in understan ding the properties of layered manganites.