With this award from the Major Research Instrumentation (MRI) program, Professor Bart Bartlett and colleagues Vincent Pecoraro, Wei Lu, Nicolai Lehnert and Stephen Maldonado from University of Michigan will acquire a very specialized superconducting quantum interference device (SQUID) capable of performing both DC (direct current-static) and AC (alternating current-dynamic) magnetometry for measurements of magnetic moments. The proposal is aimed at enhancing research training and education at all levels, especially in areas of study such as spin structure of transition metal oxides, Hall resistivity measurements in thin film semiconductors, high-spin molecules for information storage, electronic structure of enzymes functional in nitric oxide (NO) reduction, and charge ordering within battery cathode materials.
A SQUID magnetometer is critical for studying magnetic moments of molecules that have unpaired electrons, particularly for weakly magnetic/small moment samples. The large magnetic field generated by a magnet in the instrument interacts with these unpaired electrons in the various materials under study. In a DC magnetization measurement, one measures the magnetic moment as a function of applied DC magnetic field (and/or temperature). Using DC magnetization experiments, one can determine magnetic moments or a hysteresis curve, or identify magnetic phase transitions. This type of magnetometer also can be used to carry on measurements using a direct current. Magnetism is instrumental in many fields including data transfer in computation devices, biological systems and to understand magnetic processes in inorganic and bioinorganic materials. This instrument will be used in research and for training of the new generation of students in this important field.
magnetometer, allowing researchers to study simultaneously the magnetic properties of molecules and materials with the physical stimuli of temperature, applied field, light, and electricity. Intellectual Merit. The study of electronic structure, including spin structure, is vital for a complete understanding of the reactivity and physical properties of molecules and materials. Moreover, the ability to study cooperative physical phenomena is paramount to guide the synthesis of new compositions of matter, understand chemical reactivity, and explain the mechanisms of charge and ion transport. The SQUID magnetometer purchased with the NSF grant allows us to study directly spin physics in response to the applied stimuli of electrical current, photo-driven changes in magnetic properties using a fiber optic sample holder, and dynamic spin properties with the AC package. For biological applications in which a large diamagnetic protein backbone render molecules extremely dilute, the instrument is equipped with ultra-low-field capabilities for detailed studies of spin structure. This is an excellent instrument that has been customized for the comprehensive examination of the confluence of electrical, optical, and magnetic properties of materials. Broader Impacts. The scientific challenges outlined above require dedicated practice in performing physical characterization methods on molecules and materials. The impact of our program is far-reaching, and includes researchers in several departments on campus—chemistry, mechanical engineering, and materials science and engineering. In addition, the scholars working in our laboratories come from chemistry, applied physics, engineering, and industry. Co-workers in our research teams have learned to use the SQUID instrument, and seven new users have been trained during this proposal period. In addition, this instrument serves the teaching mission of the university. We have developed a lab module to implement in our advanced synthesis laboratory course. The commitment to diversity at the University of Michigan ensures that students from various backgrounds are trained to tackle research problems in the study of advanced materials. Students are our most valuable resource, and in the 21st Century, electronic and magnetic characterization of materials has become a routine part of the undergraduate curriculum. Outcomes of the Award. The suite of equipment for the SQUID instrument was purchased and the instrument was installed on August 26, 2011. Since then, seven new users have been trained in magnetic characterization of materials. A new lab module has been developed. The SQUID magnetometer has been in continuous use since its installation.
