Workshop Support: "Magnetism, Hysteresis and the FORC Method"

去年，加州大学戴维斯分校收到了美国国家科学基金会主要研究仪器项目(NSF-MRI)的资助(EAR-02-16346)。这笔题为“提高加州大学戴维斯分校磁性材料表征能力”的赠款为购买交流梯度和振动样品磁强计(AGM/VSM)提供资金。该仪器将致力于利用一阶反转曲线(FORCs)进行研究，这是一种研究天然和合成样品磁性的新技术。新仪器的高磁场和高低温能力使其能够在比迄今可能的更大的温度和磁场范围内获取力数据。Forc方法使用部分滞后曲线来获得有关样品中磁性颗粒分布的信息，而不仅仅是它们的平均值。此外，它还可用于研究样品中的磁相互作用。由于这些原因，该方法可以比使用主要磁滞回线或许多传统形式的磁测量方法更详细地探测磁行为的微观机制。尽管FORC方法最初是为了研究自然地质样本而开发的，但它也有潜在的应用于其他领域，加州大学戴维斯分校的一个由地球科学家、凝聚态物理学家和材料科学家组成的跨学科团队已经使用该方法研究先进的磁性介质、自旋玻璃和磁性纳米结构。为了尽可能有效地传播有关FORC方法的信息，这笔赠款将为国际和美国科学家参加题为“磁性、磁滞和FORC方法”的研讨会提供旅费。研讨会将于2003年4月25日至27日在戴维斯校园举行，组委会由肯·维罗苏布(地球物理学家)、刘凯(材料科学家)、理查德·斯卡莱塔尔和格格利·齐曼伊(两人都是物质物理学家)组成。在研讨会上，与会者将有机会了解FORC方法及其应用，听取关于当前磁学和磁滞问题的特邀论文，参与讨论这些问题与FORC方法之间的关系，并获得绘制FORC图的实践经验。***

0330784VerosubLast year, the University of California, Davis, received a grant (EAR-02-16346) from the NSF Major Research Instrumentation (NSF-MRI) program. The grant, entitled "Enhancing the Capabilities for Characterization of Magnetic Materials at the University of California, Davis", provided funds for the purchase of a combined alternating gradient and vibrating sample magnetometer (AGM/VSM). This instrument will be dedicated to research using first-order reversal curves (FORCs), a new technique for studying the magnetic properties of natural and synthetic samples. The high magnetic field and high and low temperature capabilities of new instrument make it possible to acquire FORC data over a greater range of temperatures and magnetic fields than has heretofore been possible. The FORC method uses partial hysteresis curves to obtain information about the distribution of magnetic grains in a sample, rather than just their average value. In addition, it can be used to study magnetic interactions within a sample. For these reasons, the method can probe the microscopic mechanisms of magnetic behavior in greater detail than is possible with major hysteresis loops or with many conventional forms of magnetometry. Although it was originally developed to study natural geologic samples, the FORC method has potential applications to other fields, and an interdisciplinary team of earth scientists, condensed matter physicists and material scientists at UC Davis has already used the method to study advanced magnetic media, spin glasses and magnetic nanostructures. In order to disseminate information about the FORC method as effectively as possible, this grant will provide travel support for international and U.S. scientists to attend a workshop entitled "Magnetism, Hysteresis and the FORC Method". The workshop will take place April 25-27, 2003, on the Davis campus, and the organizing committee consists of Ken Verosub (a geophysicist), Kai Liu (a material scientist), and Richard Scalettar and Gergely Zimanyi (both condenses matter physicists). At the workshop, participants will have the opportunity to learn about the FORC method and its applications, to listen to invited papers on current issues in magnetism and hysteresis, to participate in discussions about the relationship between these issues and the FORC method, and to obtain hands-on experience at creating FORC diagrams. ***