Non-contact conductivity measurement

Patent metadata

Field	Value
Publication number	US-9176175-B2
Application number	US-201313969336-A
Country	US
Kind code	B2
Filing date	Aug 16, 2013
Priority date	Mar 14, 2013
Publication date	Nov 3, 2015
Grant date	Nov 3, 2015

Abstract

A method for analyzing a material-under-test includes levitating a free-floating magnet between a material-under-test and a diamagnet and a mounted magnet, such that the diamagnet is positioned between the mounted magnet and the free-floating magnet, measuring a rotation rate of the free-floating magnet over time, and calculating at least one of a conductivity and resistivity of the material-under-test based on the measured rotation rate of the free-floating magnet over time.

First claim

What is claimed is:

1. A method for analyzing a material-under-test, comprising:
levitating a free-floating magnet between a material-under-test, a diamagnet mounted to a support structure, and a mounted magnet, such that the diamagnet is positioned between the mounted magnet and the free-floating magnet;
rotating the free-floating magnet in a physically separated manner with respect to the material-under-test;
measuring a rotation rate of the free-floating magnet over time with a rotation detection assembly based on measuring a reflection of a laser beam projected toward the free-floating magnet, the rotation rate increasing or decreasing based on a drag torque effect of the material-under-test on the free-floating magnet; and
calculating, via a conductivity calculation unit in electrical communication with the rotation detection assembly, at least one of a conductivity and resistivity of the material-under-test based on the measured rotation rate of the free-floating magnet over time.

2. The method of claim 1 , further comprising:
rotating the material-under-test to generate a rotating drag for torque that induces the rotation of the floating magnet; and
calculating the at least one of the conductivity and the resistivity of the material-under-test by measuring the increase in the rotation rate of the free-floating magnet over time.

3. The method of claim 1 , further comprising:
initiating rotation of the free-floating magnet with respect to the material-under-test;
maintaining stationary the material-under-test to apply a stationary drag torque upon the free-floating magnet, the stationary drag torque inhibiting the rotation of the free-floating magnet; and
calculating the at least one of the conductivity and the resistivity of the material-under-test by measuring the decrease in the rotation rate of the free-floating magnet over time.

4. The method of claim 3 , wherein initiating the rotation of the free-floating magnet includes applying a force to the free-floating magnet with a solenoid disposed adjacent to the free-floating magnet, the solenoid including a coil and an armature.

5. The method of claim 3 , wherein initiating the rotation of the free-floating magnet includes applying a force to the free-floating magnet with a magnetic field generated by a stator coil that is disposed adjacent to the free-floating magnet.

Assignees

• IBM

Inventors

• Gunawan Oki

Classifications

• G01N27/72 Primary

  by investigating magnetic variables · CPC title

• G01N27/04

  by investigating resistance · CPC title

• G01R27/32 Primary

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title