George W Crabtree

US Patent:

6638895, Oct 28, 2003

Filed:

Oct 25, 2000

Appl. No.:

09/696050

Inventors:

Goran T. Karapetrov - Naperville IL
Wai-Kwong Kwok - Downers Grove IL
George W. Crabtree - Chicago IL
Maria Iavarone - Casoria, IT

Assignee:

The University of Chicago - Chicago IL

International Classification:

H01L 3924

US Classification:

505320, 505325, 505410, 505413, 438705, 20415744, 216 87, 216 96

Abstract:

A method of fabricating high aspect ratio ceramic structures in which a selected portion of perovskite or perovskite-like crystalline material is exposed to a high energy ion beam for a time sufficient to cause the crystalline material contacted by the ion beam to have substantially parallel columnar defects. Then selected portions of the material having substantially parallel columnar defects are etched leaving material with and without substantially parallel columnar defects in a predetermined shape having high aspect ratios of not less than 2 to 1. Etching is accomplished by optical or PMMA lithography. There is also disclosed a structure of a ceramic which is superconducting at a temperature in the range of from about 10Â K. to about 90Â K. with substantially parallel columnar defects in which the smallest lateral dimension of the structure is less than about 5 microns, and the thickness of the structure is greater than 2 times the smallest lateral dimension of the structure.

US Patent:

6972562, Dec 6, 2005

Filed:

Sep 22, 2004

Appl. No.:

10/945953

Inventors:

Vitalii K. Vlasko-Vlasov - Downers Grove IL, US
Ulrich Welp - Lisle IL, US
George W. Crabtree - Chicago IL, US

Assignee:

The United States of America as represented by the United States Department of Energy - Washington DC

International Classification:

G01R033/032
G01R033/02

US Classification:

3242441, 324260, 324753

Abstract:

A device and method for mapping magnetic fields of a sample at a resolution less than the wavelength of light without altering the magnetic field of the sample is disclosed. A device having a tapered end portion with a magneto-optically active particle positioned at the distal end thereof in communication with a fiber optic for transferring incoming linearly polarized light from a source thereof to the particle and for transferring reflected light from the particle is provided. The fiber optic has a reflective material trapping light within the fiber optic and in communication with a light detector for determining the polarization of light reflected from the particle as a function of the strength and direction of the magnetic field of the sample. Linearly polarized light from the source thereof transferred to the particle positioned proximate the sample is affected by the magnetic field of the sample sensed by the particle such that the difference in polarization of light entering and leaving the particle is due to the magnetic field of the sample. Relative movement between the particle and sample enables mapping.