Magnetic and electronic properties in hole-doped manganese oxides with layered structures: La_1-xSr_1+xMnO₄

Electrical resistivity (ρ) and magnetic susceptibility (χ) were measured for single crystals of La_1-xSr_1+xMnO₄ (0.0≤x≤0.7), which were grown by the floating-zone method with varying the nominal hole concentration (x). With hole doping, critical temperature (T_N) for the antiferromagnetic phase transition decreases and eventually a spin-glass phase appears for x≥0.2, perhaps due to the competition between the generic antiferromagnetic superexchange interaction and the ferromagnetic double-exchange interaction. At x≊1/2, real-space ordering of the doped holes occurs at ∼220 K, accompanying a steep increase of ρ as well as a suppression of χ.