新規な無機ハイブリッド型層状遷移金属硫化酸化物Sr_2Cu(Fe,Ga)O_3Sおよび(Sr,La)_4Cu_2Mn_3O_<7.5>S_2の合成と評価 : 磁性体物理

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New layered oxysulfides, Sr_2CuFe_<1-x>Ga_xO_3S (x = 0, 0.05) and Sr_<4-x>La_xCu_2Mn_3O_<7.5>S_2 (x = 0, 0.10, 0.20, 0.40) with alternating Cu_2S_2 and perovskite oxide layers were synthesized and characterized. The perovskite oxide layers in Sr_2 CuMO_3S (M = Fe and Ga) and A_4Cu_2Mn_3O_<7.5>S_2 (A = Sr and La) have stacking sequences with -MO_2-SrO-SrO-MO_2- and -MnO_2-AO-MnO_<1.5>-AO-MnO_2-, respectively. Sr_2CuFe_<1-x>Ga_xO_3S (x = 0, 0.05) is semiconducting. The electrical resistivity of the x = 0.05 sample is ten times lower than that of the x = 0 sample, indicating that the conduction path is in the Ga-introduced Fe oxide layer. Sr_4Cu_2Mn_3O_<7.5>S_2 exhibits a phase transition from paramagnetic to antiferromagnetic states below 100 K. In Sr_<4-x>La_xCu_2Mn_3O_<7.5>S_2 (x = 0, 0.10, 0.20, 0.40), the lattice parameters a and c decrease with increasing x. All samples are semiconducting. The electrical resistivity dramatically falls with increasing x; that of the x = 0.40 sample is one hundred times lower than that of the x = 0 sample.
社団法人日本磁気学会の論文
2002-04-01