Phase Diagram of Tetragonal Manganites

The phase diagram of La_1-xSrₓMnO₃, as a function of hole doping x and tetragonal distortion $c/a$, which consists of ferromagnetic (FM), A-, C-, and G-type antiferromagnetic (AF) states, is obtained by the first-principles band structure calculations. Effects of tetragonal distortion on the magnetic ordering are discussed in terms of orbital ordering and anisotropy in the hopping integrals. The general sequence of the magnetic ground states, FM → A-AF → C-AF → G-AF with increasing of x, is also explained based on the instability of FM states with respect to the spin-wave excitations.