National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2010 Dec 17;105(25):257204. doi: 10.1103/PhysRevLett.105.257204. Epub 2010 Dec 14.
We present an unreported magnetic configuration in epitaxial La(1-x) Sr(x) MnO3 (x ∼ 0.3) (LSMO) films grown on strontium titanate (STO). X-ray magnetic circular dichroism indicates that the remanent magnetic state of thick LSMO films is opposite to the direction of the applied magnetic field. Spectroscopic and scattering measurements reveal that the average Mn valence varies from mixed Mn(3+)/Mn(4+) to an enriched Mn3+ region near the STO interface, resulting in a compressive lattice along the a, b axis and a possible electronic reconstruction in the Mn e(g) orbital (d(3)z(2)-r(2). This reconstruction may provide a mechanism for coupling the Mn3+ moments antiferromagnetically along the surface normal direction, and in turn may lead to the observed reversed magnetic configuration.
我们提出了一种在钛酸锶（STO）上生长的外延 La(1-x) Sr(x) MnO3（x ∼ 0.3）（LSMO）薄膜中未报道的磁组态。X 射线磁圆二色性表明，厚 LSMO 薄膜的剩余磁状态与施加磁场的方向相反。光谱和散射测量表明，平均 Mn 价态从混合 Mn(3+)/Mn(4+)变化到 STO 界面附近的富 Mn3+区域，导致沿 a、b 轴的压缩晶格和 Mn e(g)轨道（d(3)z(2)-r(2)的可能电子重构。这种重构可能为 Mn3+ 磁矩沿表面法向反铁磁耦合提供了一种机制，并反过来可能导致观察到的反向磁组态。
