Spin-polarized intergrain tunneling in La-2/Sr-3(1)/3MnO3
Spin-polarized intergrain tunneling in La-2/Sr-3(1)/3MnO3
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DOI：
10.1103/physrevlett.77.2041
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发表时间：
1996-09-02
影响因子：
8.6
通讯作者：
Batlogg, B
中科院分区：
文献类型：
--
作者：
Hwang, HY;Cheong, SW;Batlogg, B
系统地研究了La2/3Sr1/3MnO3单晶和多晶La2/3Sr1/3MnO3低温铁磁金属态的磁电阻(MR)和随场变化的磁化强度。我们发现，单晶中的本征负磁阻是由于自旋涨落的抑制，而磁畴边界并不主导散射过程。相反，我们发现多晶样品中的磁流变区有两个明显的区域：低场下以自旋极化隧道效应为主的大磁流变区和5-280K温度范围内显著不受温度影响的高场磁流变区。
The magnetoresistance (MR) and the field dependent magnetization have been systematically examined in the low temperature ferromagnetic metallic state of single crystal and polycrystalline La2/3Sr1/3MnO3. We find that the intrinsic negative MR in single crystal is due to the suppression of spin fluctuations, and magnetic domain boundaries do not dominate the scattering process. In contrast, we demonstrate that the MR in the polycrystalline samples exhibits two distinct regions: large MR at low fields dominated by spin-polarized tunneling between grains and high field MR which is remarkably temperature independent from 5 to 280 K.