Magnetic and electrical properties of Bi1-xSrxMnO3: Hole-doping effect on ferromagnetic perovskite BiMnO3
Magnetic and electrical properties of Bi1-xSrxMnO3: Hole-doping effect on ferromagnetic perovskite BiMnO3
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DOI：
10.1006/jssc.1997.7432
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发表时间：
1997-08-01
影响因子：
3.3
通讯作者：
Syono, Y
中科院分区：
文献类型：
--
作者：
Chiba, H;Atou, T;Syono, Y
虽然La3+和Bi3+离子具有相似的离子半径，但发现Bi1-xSrxMnO3体系表现出与La1-xSrxMnO3体系完全不同的行为，其中La1-xSrxMnO3体系通过“双交换机制”获得具有金属导电性的铁磁性。高压下合成的BiMnO3是一种T-c=105 K的铁磁绝缘体，与反铁磁LaMnO3相反。虽然在BiMnO3中Sr取代增加了电导率，但在x=0.67的固溶体极限之前没有金属态。此外，BiMnO3的饱和磁矩为3.6 mu(B)，随着x的增加而迅速下降，当x>0.4时铁磁性消失。这些观察结果表明，具有6s(2)孤对的高极化Bi3+离子会引起钙钛矿晶格的局部畸变，这可能会降低载流子的迁移率。BiMnO3铁磁性的起源需要双交换理论以外的机制。(C) 1997学术出版社。
Although La3+ and Bi3+ ions have similar ionic radii, the Bi1-xSrxMnO3 system was found to show quite different behavior from La1-xSrxMnO3 in which ferromagnetism with metallic conductivity is achieved by the ''double exchange mechanism.'' BiMnO3 which was synthesized under high pressure is a ferromagnetic insulator with T-c=105 K, in contrast to antiferromagnetic LaMnO3. Though Sr substitution in BiMnO3 increased conductivity, no metallic state was achieved up to the solid solution limit of x=0.67. Furthermore the saturation magnetic moment of 3.6 mu(B) observed in BiMnO3 decreased very rapidly with increasing x, and ferromagnetism disappeared for x>0.4. These observations suggest that the highly polarizable Bi3+ ion with 6s(2) lone pair would cause local distortion of the perovskite lattice, which presumably reduces the mobility of carriers. The origin of ferromagnetism in BiMnO3 requires a mechanism other than the double exchange theory. (C) 1997 Academic Press.