High-pressure high-temperature synthesis and magnetic properties of ordered perovskite Sr_2Cu(Re_(0.69_x)W_xCa_(0.31))O_6 (0<=x<=0.6)

摘要

We report the synthesis and magnetic properties of polycrystalline Sr_2Cu(Re_(0.69_x)W_xCa_(0.31))O_6 samples with x=0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6, which were prepared by high-pressure high-temperature synthesis technique. These phases had ordered cubic perovskite structures. The pristine compound (x=0) underwent a ferromagnetic (ferrimagnetic) transition with T_C approx 460 K. The ferromagnetism was suppressed by the W substitution and disappears almost completely for x=0.6. Mechanism of the suppression of the magnetism is discussed assuming a localized electron system.