Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan.
Phys Rev Lett. 2011 May 27;106(21):217204. doi: 10.1103/PhysRevLett.106.217204. Epub 2011 May 26.
We uncover a strong anisotropy in both the anomalous Hall effect (AHE) and the magnetoresistance of the chiral spin states of Pr(2)Ir(2)O(7). The AHE appearing below 1.5 K at a zero magnetic field shows hysteresis which is most pronounced for fields cycled along the [111] direction. This hysteresis is compatible with the field-induced growth of domains composed by the 3-in 1-out spin states which remain coexisting with the 2-in 2-out spin ice manifold once the field is removed. Only for fields applied along the [111] direction, we observe a large positive magnetoresistance and Shubnikov-de Haas oscillations above a metamagnetic critical field. These observations suggest the reconstruction of the electronic structure of the conduction electrons by the field-induced spin texture.
我们发现 Pr(2)Ir(2)O(7) 中手性自旋态的反常霍尔效应（AHE）和磁阻都具有很强的各向异性。在零磁场下，低于 1.5 K 的 AHE 表现出滞后现象，在沿 [111] 方向循环磁场时最为明显。这种滞后现象与由 3-in-1-out 自旋态组成的畴的场诱导生长是一致的，一旦磁场被移除，这些自旋态仍然与 2-in-2-out 自旋冰 manifold 共存。只有在沿 [111] 方向施加磁场时，我们才观察到在超磁转变临界场以上的大的正磁电阻和舒布尼科夫-德哈斯振荡。这些观察结果表明，磁场诱导的自旋织构对传导电子的电子结构进行了重构。
