物理系学术报告：Probing Materials Using Radioactive Local Probes: An Introduction to the μSR and βNMR Techniques

报告题目： Probing Materials Using Radioactive Local Probes: An Introduction to the μSR and βNMR Techniques 报告人： Dr. Iain McKenzie TRIUMF, Vancouver, Canada 报告时间： 2013年5月6日 10:30 报告地点：三楼报告厅C302 摘要： The Centre for Molecular and Materials Science (CMMS) at TRIUMF provides intense beams of spin-polarized muons and radioactive ions for Canadian and international researchers to probe materials at the molecular level. Material properties are determined using a series of magnetic resonance techniques known as μSR (muon spin rotation, relaxation and resonance) and βNMR (beta-detected nuclear magnetic resonance) that exploit the parity violating decay of the probes. I will review the μSR technique and give examples of how it can be used to obtain unique information about a wide range of phenomena in physics and chemistry, such as magnetic ordering and spin dynamics, internal field distributions in superconductors and the behaviour of free radicals in bulk materials. I will introduce the βNMR technique and show that it provides a window into magnetism, superconductivity and polymer dynamics near surfaces, at buried interfaces and in thin films. The CMMS facility is in the middle of a large expansion. One new μSR beam line with two end stations and the capability of performing high frequency and long time range measurements is being commissioned and a second new μSR beam line is nearing completion. We are also expecting a three-fold increase in the time available for βNMR experiments due to the construction of the Advanced Rare Isotope Laboratory (ARIEL). We are actively seeking new experiments to make use of our world-leading facilities. Background： TRIUMF is one of the world’s leading subatomic physics laboratories. It is located in Vancouver, Canada. Dr. Iain McKenzie is an expert in the field of applying muon spin rotation/resonance/relaxation spectroscopy in chemistry and soft matter physics. His current research is focused on using μSR and βNMR to probe the microscopic dynamics of polymers and liquid crystals. He is also in charge of the μSR and NMR facilities in TRIUMF. One of his main responsibilities is to interact with potential users and improve the accessibility.