论文标题
简化的方法评估鱿鱼磁力计中常用蓝宝石底物的磁各向异性
A Simplified Method of the Assessment of Magnetic Anisotropy of Commonly Used Sapphire Substrates in SQUID Magnetometers
论文作者
论文摘要
固态晶圆是材料科学中必不可少的组成部分，作为二维材料的外延均或异性结构或载体的底物。但是，体积磁力测定法中纳米材料的磁性的可靠测定通常会受到这些底物的意外富含磁性的影响，包括明显的磁各向异性。在这里，我们描述了一种简化的磁各向异性评估的实验惯例，我们为来自各种来源的Epi-Ready Sapphire Wafers进行了例证和验证。磁各向异性的强度和符号都是从精心设计的依赖温度的测量值中获得的，这些测量可减轻所有已知的体积鱿鱼磁力测定法的陷阱，并且比传统方法要快得多。我们的测量表明，在所有样品中，两种类型的净顺磁性贡献与Diamagnetism共存。第一个可以高达蓝宝石的基本diamagnetism的10％[-3.7（1）x 10-7 emu/goe]，并且当超过2％的标记时，它表现出明显的磁各向异性，其易于轴垂直于c-Plane Wafers的脸部。另一个弱得多，但表现出类似铁磁的外观。这些发现构成了一个重要的信息，即普通底物的非标准磁性可以显着影响纳米级材料精确磁力测定的结果，其存在必须被工业和学术界授予。
Solid state wafers are indispensable components in material science as substrates for epitaxial homo- or hetero-structures or carriers for two-dimensional materials. However, a reliable determination of magnetic properties of nanomaterials in volume magnetometry is frequently affected by unexpectedly rich magnetism of these substrates, including significant magnetic anisotropy. Here, we describe a simplified experimental routine of magnetic anisotropy assessment, which we exemplify and validate for epi-ready sapphire wafers from various sources. Both the strength and the sign of magnetic anisotropy is obtained from carefully designed temperature dependent measurements, which mitigate all known pitfalls of volume SQUID magnetometry and are substantially faster than traditional approaches. Our measurements indicate that in all the samples two types of net paramagnetic contributions coexists with diamagnetism. The first one can be as strong as 10% of the base diamagnetism of sapphire [-3.7(1) x 10-7 emu/gOe], and, when exceeds 2% mark, it exhibits pronounced magnetic anisotropy with the easy axis oriented perpendicularly to the face of c-plane wafers. The other is much weaker but exhibit ferromagnetic-like appearance. These findings form an important message that non-standard magnetism of common substrates can significantly influence the results of precise magnetometry of nanoscale materials and its existence must be taken for granted by both industry and academia.
