Materials

UBC Superconductivity:
Materials Research

The core of our research is materials development, since sample growth and characterization are crucial to all of our other efforts. We have three laboratories devoted to materials: a solid state chemistry lab, a thin film lab, and a characterization lab featuring a Quantum Design SQUID Magnetometer. There is also a wide range of other materials facilities in the AMPEL building, such as a fully outfitted cleanroom and X-ray crystallography lab (see the facilities page). The materials aspect of our research affords students an opportunity to become involved in the chemistry as well as the physics of materials. It also brings us into contact with numerous researchers worldwide who make use of the samples produced at UBC Vancouver.

We have a fully-outfitted solid state chemistry lab used mainly for the growth of high quality crystals. The crystal growth effort is aimed at developing the high-quality samples required for investigating the fundamental properties of high temperature superconducting materials.
		We also have a film growth lab, focussed on the production of films by laser ablation. The lab's main aim is development of materials and processing suitable for electronic applications of superconductors and is described in more detail under Applied Research.

At the present time, the main materials project is the development of very high purity samples of YBCO grown in homemade BaZrO₃ crucibles. Recent thrusts include manipulating the doping of these materials to the edge of where they cease to be superconducting and a study of phases which exhibit oxygen ordering. We are also continuing to study the effects of various impurities such as Zn, Ni, and Ca on the properties of single crystals of YBCO.
		Research in this area of materials involves technical expertise in areas ranging over solid state chemistry, physics, and ceramic engineering. The materials research drives a wide range of technical projects such as Ruixing Liang's development of the custom-made 3-zone furnace depicted here.

One of our students, Darren Peets, has been working on the growth of single-crystalline Tl₂Ba₂CuO_6+x (Tl-2201). This compound is an intrinsically overdoped single-layer cuprate, making it of great interest to the field. However, it has been poorly studied due to issues arising from the extreme toxicity and volatility of thallium oxide. These considerations make the crystal growth process awkward and arduous.
		While we have succeeded in growing mm-sized crystals of this compound, a great deal of work lies ahead. For instance, the growth technique needs to be optimized and several oxygen annealing issues are still being dealt with.