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Magnetic Field Microprobe Using Controlled Emission of Radiation

IP.com Disclosure Number: IPCOM000085757D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 40K

Publishing Venue

IBM

Related People

Thompson, DA: AUTHOR

Abstract

A magnetic microprobe in Fig. 1 uses ultraviolet radiation from source 10, and a microscope 11 to inspect a magnetic recording head 16 with mono-molecular dye layer 12 and mirror layers 13. It is adapted to measure a head 16 under study which is encapsulated in glass 15.

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Magnetic Field Microprobe Using Controlled Emission of Radiation

A magnetic microprobe in Fig. 1 uses ultraviolet radiation from source 10, and a microscope 11 to inspect a magnetic recording head 16 with mono- molecular dye layer 12 and mirror layers 13. It is adapted to measure a head 16 under study which is encapsulated in glass 15.

A fluorescent dye excited by ultraviolet radiation is required while any excited particle with a magnetic moment can be used. Similarly, the emitted radiation is called light, although electromagnetic radiation of any wavelength can be used. For phonons this requires a material interface with an analogous relationship involving the reflectivities to shear and compressive waves.

The basic principle of the method is shown in Figs. 2A and 2B.

If an oscillating dipole is held parallel to and much less than a wavelength from A mirror, the mirror image enhances the radiation of the dipole. Similarly, if the dipole is perpendicular to the mirror the radiation is inhibited. If the dipole is held a quarter wavelength away, the effects are reversed. In general the spacing affects both the intensity and angular distribution of the radiation.

A more complete description is found on pages 117-119 of Drexhage, Karl H., "Monomolecular Layers and Light", Scientific American 222, No. 3, p. 108-119 (March 1970).

A magnetic oscillator, such as the orange fluorescence of the europium dye discussed in the reference, is oriented to some extent by an applied magnetic field. If the temperature is low enough or the magnetic field large enough, this orientation has a significant effect on the emission probability of each polarization. Thus, the device consisting of a mirror, a number of spacing layers, and a monomolecular dye layer, as described by the authors of the reference, might be used to measure magnetic field. It would probably not be a practical device, however, since the temperature sensitivity and fluctuation in output due to other variables would make it difficult to calibrate.

Suppose, however, than an alternating magnetic field is applied which is small compared to the field to be measured, but large enough to produce resonance saturation at the magnetic resonance frequency. In areas of the dy...