Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstraße 20, Dresden, Germany.
Nanotechnology. 2012 Jun 29;23(25):255701. doi: 10.1088/0957-4484/23/25/255701. Epub 2012 May 31.
Magnetotransport of individual rolled-up Fe(3)Si nanomembranes is investigated in a broad temperature range from 4.2 K up to 300 K in pulsed magnetic fields up to 55 T. The observed magnetoresistance (MR) has the following pronounced features: (i) MR is negative in the investigated intervals of temperature and magnetic field; (ii) its magnitude increases linearly with the magnetic field in a low-field region and reveals a gradual trend to saturation when the magnetic field increases; (iii) the MR effect becomes more pronounced with increasing temperature. These dependences of MR on the magnetic field and temperature are in line with predictions of the spin-disorder model of the spin-flip s-d interaction assisted with creation or annihilation of magnons, which is expected above a certain critical temperature. Comparison of the MR features in rolled-up and planar samples reveals a substantial increase of the critical temperature in the rolled-up tube, which is attributed to a new geometry and internal strain arising in the rolled-up nanomembranes, influencing the electronic and magnetic properties of the material.
在从 4.2 K 到 300 K 的宽温度范围内，在高达 55 T 的脉冲磁场中研究了单个卷起的 Fe(3)Si 纳米膜的磁输运。观察到的磁电阻（MR）具有以下明显特征：（i）MR 在研究的温度和磁场间隔内为负；（ii）在低场区域，其幅度随磁场线性增加，并在磁场增加时显示出逐渐饱和的趋势；（iii）MR 效应随温度升高而变得更加明显。这些 MR 对磁场和温度的依赖性与自旋翻转 s-d 相互作用的自旋无序模型的预测一致，预计在一定的临界温度以上会出现这种情况。将卷起和平面样品的 MR 特征进行比较，揭示了卷起管中的临界温度有了很大的提高，这归因于卷起的纳米膜中出现的新几何形状和内部应变，这会影响材料的电子和磁性质。
