Diluted magnetic interactions in an oxygen-deficient perovskite cobaltite: magnetoresistance in the series SrCo1−xScxO3−δ (0
Diluted magnetic interactions in an oxygen-deficient perovskite cobaltite: magnetoresistance in the series SrCo1−xScxO3−δ (0
复制标题
缺氧钙钛矿钴矿中的稀释磁相互作用：SrCo1−xScxO3−δ 系列中的磁阻（0
DOI：
10.1016/j.jssc.2004.06.029
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发表时间：
2004
影响因子：
3.3
通讯作者：
V. Caignaert
中科院分区：
文献类型：
--
作者：
A. Maignan;D. Pelloquin;D. Flahaut;V. Caignaert
通过使用成分范围为 0.05⩽x⩽0.5 的密闭安瓿，成功制备了一系列缺氧钙钛矿 SrCo1−xScxO3−δ。 x 引起的晶胞膨胀归因于 Sc3+ 离子半径比 Co3+/Co4+ 阳离子半径更大。在 300K 时，当 x=0.05 和 0.10 时，测量到的电阻率 (ρ) 值约为 ∼10−2Ωcm，但对于较大的 x 值，ρ 会增加，在 x=0.5 时达到 ρ300K=102Ωcm。对于前者，较低的电阻率值源于其弱铁磁行为，其特征在于居里温度TC约为60K。有趣的是，这些氧化物表现出与 SrFe1−xCoxO3−δ 样品报道的相似的负磁阻值，在 7T、5K 下达到 12%。结论是，替代钴的非磁性 (3d0) Sc3+ 物质和氧空位的同时存在会引起磁无序，例如 SrCo0.5Sc0.5O3−δ 的自旋玻璃样行为，这有利于磁阻的存在。
A series of the oxygen-deficient perovskite SrCo1−xScxO3−δhas been successfully prepared by using close ampoules for compositions in the range 0.05⩽x⩽0.5. The unit cell expansion with x is ascribed to the larger Sc3+ionic radius than those of the Co3+/Co4+cations. At 300K, resistivity (ρ) values of about ∼10−2Ωcm are measured for both x=0.05 and 0.10, but for larger x values ρ increases, reaching ρ300K=102Ωcm for x=0.5. For the former, the lower resistivity values result from their weak ferromagnetic behavior characterized by a Curie temperature TCof ∼60K. Interestingly, these oxides exhibit similar negative magnetoresistance values, reaching 12% in 7T at 5K, to those reported for the SrFe1−xCoxO3−δsamples. It is concluded that the simultaneous presence of non-magnetic (3d0) Sc3+species, substituted for cobalt, and of oxygen vacancies induce magnetic disordering, exemplified by the spin-glass like behavior of SrCo0.5Sc0.5O3−δ, which favors the existence of magnetoresistance.