Measuring Magnetism

2018-02-09 Dr. Robert D. Shull

ABSTRACT :

Magnetic materials are used all around the world for all sorts of different applications like power generation, data storage, transmission of electricity, motion and location sensors, motors, airport screening, etc. In fact they are indemic to our society. However, how do the properties of these materials vary, and how does one measure those “magnetic” properties or design a material to have a particular magnetic property? This presentation will give an overview of how to measure these things, giving examples of their application to the examination of new technological materials. Also, how do you know that the value of the saturation magnetization in your sample is 3.8 Am2/kg (e.g., 3.8 emu/g) and not actually 3.9 Am2/kg? Or maybe you don’t care. Just because your measurement equipment reads out 3.8 emu/g, can you really believe it? This presentation will also introduce the concept of calibration and “standards,” both physical and computational. As time permits, the presentation will also include a description of two relatively new magnetic characterization tools, one of which was developed at NIST, that can provide unique information about the materials. One of them, the First Order Reversal Curve (FORC) method, enables the characterization of materials made up of composites of things, including particle collections, multiple phases, and regions of different magnetic character. The other tool, the Magneto-Optic Indicator Film (MOIF) technique enables the real time imaging of magnetic domains in a ferromagnet (especially in thin films), so that magnetization dynamics can be studied when a field is applied.

Event Name

Seminars

Place

Seminar Room

Start Time

15:00

End Time

16:00

External Link

PDF to Talk