KYOKUGEN, Osaka University, Toyonaka, Osaka, Japan.
J Phys Condens Matter. 2011 Mar 23;23(11):112205. doi: 10.1088/0953-8984/23/11/112205. Epub 2011 Mar 1.
The kagome-bilayer material Fe(3)Sn(2) has recently been shown to be an example of a rare class of magnet-a frustrated ferromagnetic metal. While the magnetism of Fe(3)Sn(2) appears to be relatively simple at high temperature, with localized moments parallel to the c-axis (T(C) = 640 K), upon cooling the competing exchange interactions and spin frustration become apparent as they cause the moments to become non-collinear and to rotate towards the kagome plane, forming firstly a canted ferromagnetic structure and then a re-entrant spin glass (T(f) approximately equal 80 K). In this work we show that Fe(3)Sn(2) possesses an unusual anomalous Hall effect. The saturated Hall resistivity of Fe(3)Sn(2) is 3.2 µΩ cm at 300 K, almost 20 times higher than that of typical itinerant ferromagnets such as Fe and Ni. The anomalous Hall coefficient R(s) is 6.7 × 10(-9) Ω cm G(-1) at 300 K, which is three orders of magnitude larger than that of pure Fe, and obeys an unconventional scaling with the longitudinal resistivity, ρ(xx), of R(s) is proportional to ρ(xx)(3.15). Such a relationship cannot be explained by either the conventional skew or side-jump mechanisms, indicating that the anomalous Hall effect in Fe(3)Sn(2) has an extraordinary origin that is presumed to be related to the underlying frustration of the magnetism. These findings demonstrate that frustrated ferromagnets, whether based on bulk materials or on artificial nanoscale structures, can provide new routes to room temperature spin-dependent electron transport properties suited to application in spintronics.
菱方-双层材料 Fe(3)Sn(2) 最近被证明是一类罕见的磁体-受挫铁磁金属的例子。虽然在高温下,Fe(3)Sn(2) 的磁性似乎相对简单,具有平行于 c 轴的局域磁矩(T(C) = 640 K),但随着冷却,竞争的交换相互作用和自旋受挫变得明显,因为它们导致磁矩变得非共线,并向菱方平面旋转,首先形成倾斜铁磁结构,然后形成再入自旋玻璃(T(f)约为 80 K)。在这项工作中,我们表明 Fe(3)Sn(2) 具有异常的反常霍尔效应。Fe(3)Sn(2) 在 300 K 时的饱和霍尔电阻率为 3.2 µΩ cm,几乎是典型巡游铁磁体如 Fe 和 Ni 的 20 倍。反常霍尔系数 R(s) 在 300 K 时为 6.7 × 10(-9) Ω cm G(-1),比纯 Fe 大三个数量级,并且服从于与纵向电阻率 ρ(xx) 的非常规标度关系,R(s) 与 ρ(xx) 的关系为 R(s)∝ρ(xx)(3.15)。这种关系不能用传统的偏斜或侧跳机制来解释,表明 Fe(3)Sn(2) 中的反常霍尔效应具有特殊的起源,据推测与磁体的受挫有关。这些发现表明,受挫铁磁体,无论是基于体材料还是基于人工纳米结构,都可以为室温自旋相关电子输运特性提供新途径,适用于自旋电子学。