Here we summarize recent progress on the study of spin ladder compounds, La2Cu2O5 (four-leg) and La8Cu7O19 (five-leg), n = 2 and 3 members of the homologous series La4+4nCu8+2nO14+8n. Following the successful crystal growth of La2Cu2O5, we grew a pure-phase five-leg system La8Cu7O19 by a modified slow cooling method. The room-temperature resistivity of the as-grown La8Cu7O19 crystal was 1.9 Ω cm, which is much lower than that of the La2Cu2O5 crystals (≈ 1.7 × 103 Ω cm). A significant drop in the resistivity (11.0 mΩ cm at 300 K) was observed upon hole doping by means of high oxygen-pressure annealing, although no transition was observed from the semiconducting behavior. In addition, a new crystal growth method to enhance hole doping level of La2Cu2O5 is shown.
ASJC Scopus subject areas