Superconducting resonators for high field quantum materials characterisation

这一专业的目标是开发超导谐振器，作为研究耦合奇异磁性材料的探测器。谐振器必须在高磁场下工作，才能获得耦合材料中的量子临界性和受挫磁性等现象。使用超导谐振器来间接表征材料是众所周知的，但以前一直依赖于在高磁场中不再超导的“传统”材料；我们希望表征的材料往往只有在如此高的磁场下才有意义。在卡迪夫大学，我们率先将超导掺硼纳米晶金刚石(BNCD)用于设备应用，卡迪夫领导的先前的研究表明，BNCD可以承受足够高的电场，使其成为用于这一目的的理想材料。我们最近还展示了一个原型装置，证明了当与感兴趣的材料耦合时，BNCD具有增强到其谐振频率所需的性质。在这个项目中，学生将使用我们的概念验证原型确定的启动参数来设计、模拟、制造和测量超导谐振器，并确定当特定材料接近设备时，在磁场下谐振频率的预测漂移。这些模拟将对该设备的实验应用进行基准测试，该设备使用基础温度为10mK、磁场高达8T的稀释冰箱进行测量。

The goal of this studentship is to develop superconducting resonators as a probe for investigating coupled exotic magnetic materials. The resonator must operate under high magnetic fields to access phenomena such as quantum criticality and frustrated magnetism in the coupled material. Using superconducting resonators for indirect materials characterisation is well-established but has previously relied on "traditional" materials that cease to superconduct in high magnetic fields; the materials we wish to characterise are often only interesting under such a high field. At Cardiff University, we have pioneered the use of superconducting boron-doped nanocrystalline diamond (BNCD) for device applications and previous Cardiff-led research has shown that BNCD can withstand sufficiently high fields to make it an ideal material for this purpose. We have also recently recently shown a prototype device demonstrating that BNCD has the properties required for an enhanced shift to its resonant frequency when coupled to a material of interest. Within this project, the student will design, simulate, fabricate and measure superconducting resonators with starting parameters determined from our proof-of-concept prototype, and determine the predicted shift in the resonant frequency under a magnetic field when specific materials are brought close to the device. The simulations will benchmark experimental applications of the device measured using a dilution fridge with a base temperature of 10mK and magnetic fields up to 8T.