论文标题
基于霍尔传感器的超导钒的磁相图的测量值
Hall Sensor Based Measurements of the Magnetic Phase Diagram of Superconducting Vanadium
论文作者
论文摘要
钒是一个元素II型超导体，具有纯超导相，涡流相和非抗渗透相。我们在本科物理实验室中设计并进行了一个低预算实验，以测量磁场距离纯钒磁盘样品的表面距离距离等温度和外部磁场的范围较近。然后，我们使用这些测量值来计算钒的超导相图。在八个温度（2.6K至5K）和磁场范围从-0.2t到0.2T的八个温度下完成测量后，我们能够检测到Meissner相（显然）和涡流相（较少清楚）。使用霍尔杆磁场与外部磁场的图形，我们能够在八个温度下对上临界场和钒的下部临界场进行粗略估计。结果通常与文献中发现的钒的相图一致，只是临界温度似乎小于5.43k和5.13k（约4.8k）。此外，我们观察到的临界场低于文献中的临界场。我们假设这主要是由于我们的钒样品中的杂质（通过Amazon.com购买），这将降低所测量的临界温度以下，这与我们的结果一致。
Vanadium is an elemental type-II superconductor which has a pure superconducting phase, a vortex phase, and a non-superconducting phase. We designed and carried out a low-budget experiment in our undergraduate physics lab to measure the magnetic field a close distance from the surface of a pure Vanadium disk sample isothermally with a Hall sensor across a range of different temperatures and external magnetic fields. We then used these measurements to compute the superconducting phase diagram of Vanadium. After completing measurements at eight temperatures ranging from 2.6K to 5K and magnetic fields ranging from -0.2T to 0.2T, we were able to detect the Meissner phase (clearly), and a vortex phase (less clearly). Using the graphs of the hall bar magnetic field versus external magnetic field, we were able to derive a rough estimate for the upper critical field and the lower critical field of Vanadium at the eight temperatures wherein we conducted measurements. The results are in general accord with the phase diagram of Vanadium found in the literature, except that the critical temperature appears to be less than 5.43K and 5.13K (about 4.8K). Further, we observed critical fields lower than those found in the literature. We hypothesize this is due mostly to impurities in our Vanadium sample (purchased through Amazon.com), which would reduce the measured critical temperature below that of pure Vanadium, consistent with our results.
