MRI: Acquisition of a Superconducting Quantum Interference Device (SQUID)

获得重大研究仪器(MRI)计划的这一奖项后，密歇根大学的Bart Bartlett教授及其同事文森特·佩科拉罗、魏鲁、Nicolai Lehnert和Stephen Maldonado将获得一种非常专业的超导量子干涉设备(SQUID)，该设备能够执行直流(静态)和交流(交流)磁测量，用于测量磁矩。这项建议旨在加强各级的研究培训和教育，特别是在研究领域，如过渡金属氧化物的自旋结构，薄膜半导体的霍尔电阻率测量，用于信息存储的高自旋分子，作用于一氧化氮(NO)还原的酶的电子结构，以及电池正极材料中的电荷有序。SQUID磁强计对于研究具有未配对电子的分子的磁矩至关重要，特别是对于弱磁/小磁矩样品。仪器中的磁铁产生的大磁场与所研究的各种材料中的这些未配对的电子相互作用。在直流磁化测量中，测量作为外加直流磁场(和/或温度)的函数的磁矩。使用直流磁化实验，可以确定磁矩或磁滞曲线，或识别磁性相变。这种类型的磁力计也可以用直流电进行测量。磁性在许多领域都很有用，包括在计算设备、生物系统中的数据传输，以及理解无机和生物无机材料中的磁性过程。该仪器将用于这一重要领域的研究和新一代学生的培训。

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.