THIN FILM MAGNETOMETER USING MAGNETIC VECTOR ROTATION

• US 3,562,638 A
• Filed: 11/18/1968
• Issued: 02/09/1971
• Est. Priority Date: 11/18/1968
• Status: Expired due to Term

• Current Assignee: Renard, Andre M.
• Original Assignee: Renard, Andre M.
• Inventors: Renard, Andre M.
• Application Number:
  US04/776,623
• Time in Patent Office: 813 Days
• US Class Current: 324/249
• CPC Class Codes: G01R 33/05 in thin-film element

Abstract

A thin magnetic film magnetometer is disclosed wherein the magnetometer has an easy axis drive component. The component of the ambient DC magnetic field in the direction of the hard axis rotates the magnetic vector of the thin film away from the easy axis. A drive rotates the vector away from its rest position with the rotation of the vector being modulated by the magnetic signal field being sensed. A sensing coil picks up output pulses in response to the disturbance of the magnetic vector which are modulated in accordance with the magnetic signal field. An electrical signal representative of the magnetic signal is obtained by demodulating or detecting the output signals of the sensing coil.

Claims

1. A magnetometer for giving an output representative of the component of a magnetic field in a predetermined direction, comprising, in combination:

a thin film of anisotropic material, containing first and second mutually perpendicular axes for alignment respectively parallel and normal to the predetermined direction of said component, said second axis coincIding with the preferred direction of magnetization of said film;

a first winding encompassing said material and having its axis aligned with the preferred direction of magnetization of said material;

driving means electrically energizing said first winding with uniform pulses of electrical current to produce an intermittent magnetic field in said material which combines with said component to cause angular oscillation of the magnetic vector of said material, the amplitude of said pulses being such that the magnitude of the combined field is always insufficient to cause reversal of the direction of magnetization of said material;

a second winding encompassing said material, and positioned to be insensitive to pulses of current in said first winding, so that said angular oscillation of said magnetic vector induces pulses of current in said second winding; and

output means connected to said second winding for actuation in accordance with the amplitude of said pulses of current, so that when said magnetometer is positioned in a magnetic field to be measured, the output means is activated in accordance with said component of the field.

2. A magnetometer as defined in claim 1 wherein said thin film magnetic material includes a plurality of thin films in juxtaposition with each other.