Magnetic properties instrumentation

A further important property of the two instruments concerns the nature of any ion sources used with them. Magnetic-sector instruments work best with a continuous ion beam produced with an electron ionization or chemical ionization source. Sources that produce pulses of ions, such as with laser desorption or radioactive (Californium) sources, are not compatible with the need for a continuous beam. However, these pulsed sources are ideal for the TOF analyzer because, in such a system, ions of all m/z values must begin their flight to the ion detector at the same instant in... 

Elemental composition Fe 69.94%, 0 36.06%. The oxide may be characterized by physical and magnetic properties and by x-ray methods. Iron may be analyzed by various instrumental techniques following acid digestion and appropriate dilution (See Iron). 

In a spectrum, the width of every mass peak is related to the performance of the instrument. An important property of the instrument is its ability to separate masses close to one another, which is called the resolving power R (resolution). R is calculated by dividing the m /z ratio of the chosen peak by its width A (m/z) (see Fig. 16.13) which is usually measured at half-height (FWHM, full width at half maximum). For magnetic sector instruments, width is traditionally measured at 10% of the peak height. 

This research was supported by the Grant in-Aid for Scientific Research (B) (No. 13450259) by Japan Society for the Promotion of Science. Thanks are due to the Instrument Center, the Institute for Molecular Science, for assistance in obtaining the magnetic properties at low temperature. 

Various adaptations that rely on force methods have been commercialised (the so-called Evans-Johnson-Matthey balance) or designed from readily available parts and described in the literature. The Evans method uses NMR and can provide variable temperature data on molecules in solution, but the technique is limited to a window where solvents stay liquid and solutes stay in solution. The one development that has been crucial to the more recent rapid development of this research field is the availability of relatively inexpensive and easy-to-use, variable temperature, variable field instrumentation, specifically the Superconducting Quantum Interference Device (SQUID) magnetometer. With a SQUID, it is possible, even for relatively inexperienced users, to determine the magnetic properties of a sample (typically 10-20 mg) as a function of temperature and applied field (down to 1.8 K and... 

Initial experiments showed that the PMDA/ODA material can be successfully cured by a ot plate bake at 280° C for 3 hours. Electrical.Loss tangent data showed that imidization was complete under these conditions. As noted before,the passivation process for bubble devices had to be optimized by using a lower temperature ( to preserve the magnetic properties of the permalloy structures).without losing the electrical insulation characteristics of the final polyimide. IR technique was used as the method of detecting complete cure. A Perkin Elmer 283 spectrometer was used for the IR analyses routinely,and in a few cases the results were checked with a Digilab FTIR instrument.Routine resolutions were 2cm with the Perkin Elmer instrument. Jh s g-dies of imide formation by IR is a well known technique ... 

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