Apparatus for generating a magnetic field and method of using said apparatus

Patent metadata

Field	Value
Publication number	US-11017828-B2
Application number	US-201816633775-A
Country	US
Kind code	B2
Filing date	Jun 25, 2018
Priority date	Jul 27, 2017
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

An apparatus for generating a magnetic field including permanent magnets arranged in a plane, each magnet being spatially separated along the plane from the adjacent magnet by a predetermined spacing, each magnet having a magnetic polarity opposed to the polarity of the adjacent magnet such that a magnetic field of adjacent magnets is oriented substantially perpendicular to the plane and in opposite directions, each magnet being spatially separated in the plane from the adjacent magnet by a nonmagnetic material. A method for programming a magnetic device or sensor device using the apparatus is also described.

First claim

What is claimed is:

1. A system comprising:
an apparatus for generating a magnetic field, the apparatus comprising a plurality of permanent magnets arranged in a plane, each magnet being spatially separated along the plane from the adjacent magnet by a predetermined spacing, each magnet having a magnetic polarity opposed to the one of the adjacent magnet such that a magnetic field of adjacent magnets is oriented substantially perpendicular to the plane and in opposite directions, each magnet being spatially separated in the plane from the adjacent magnet by a nonmagnetic material;
a magnetic device comprising a plurality of magnetic cells, each magnetic cell comprising a first magnetic layer having a first magnetization that is pinned at a low threshold temperature and freely orientable at a high threshold temperature, and a heating line physically separated from each of said plurality of magnetic cells and configured for passing a heating current pulse for heating any one of said plurality of magnetic cells; and
a plate lying in the plane, adjacent to a surface of the apparatus, the plate comprising a ferromagnetic or paramagnetic material, wherein:
the magnetic field generated by the apparatus is configured for switching the first magnetization of any one of said plurality of magnetic cells being heated at the high threshold temperature,
the apparatus is arranged to be movable above or below the magnetic device, along the plane, and
the plate is on the face of the apparatus opposed to the face on the side of the magnetic device.

2. The system according to claim 1 , wherein said predetermined spacing is between 0.25 mm and 50 mm.

3. The system according to claim 1 , wherein said predetermined spacing is between 1.2 mm and 25 mm.

4. The system according to claim 1 , wherein a lateral dimension of the magnet along the plane is between 2.5 mm and 80 mm.

5. The system according to claim 1 , wherein a lateral dimension of the magnet in the plane is between 12 mm and 50 mm.

6. The system according to claim 1 , wherein said plate has a thickness between 0.25 mm and 50 mm.

7. The system according to claim 1 , wherein said plate has a thickness between 5 mm and 25 mm.

8. The system according to claim 1 , comprising two magnets.

9. A method for using a system comprising an apparatus for generating a magnetic field, and a magnetic device; the magnetic device comprising a plurality of magnetic cells, each magnetic cell comprising a first magnetic layer having a first magnetization that is pinned at a low threshold temperature and freely orientable at a high threshold temperature, and a heating line physically separated from each of said plurality of magnetic cells and configured for passing a heating current pulse for heating any one of said plurality of magnetic cells, wherein the heating line comprises at least one first branch arranged for programming a first subset comprising one or more rows of said plurality of magnetic cells, and at least one second branch arranged for programming a second subset comprising one or more rows of said plurality of magnetic cells adjacent to said one or more rows of said plurality of magnetic cells of the first subset; the apparatus comprising a plurality of permanent magnets arranged in a plane, each magnet being spatially separated in the plane from the adjacent magnet by a predetermined spacing, each magnet having a magnetic polarity opposed to the one of the adjacent magnet such that a magnetic field of adjacent magnets is oriented substantially perpendicular to the plane and in opposite directions, each magnet being spatially separated in the plane from the adjacent magnet by a nonmagnetic material; wherein the method comprises:
heating any one of said plurality of magnetic cells to the high threshold temperature by passing the heating current pulse in the heating line;
once said any one of said plurality of magnetic cells are at the high threshold temperature, applying the magnetic field generated by the apparatus for reorienting the first magnetization of said any one of said plurality of magnetic cells;
re-orienting the reference magnetization of the magnetic cells in the first subset in a first direction; and
re-orienting the reference magnetization of the magnetic cells in the second subset in a second direction opposed to first direction,
wherein the apparatus is moved during application of the magnetic field.

10. The method according to claim 9 ,
wherein said re-orienting of the reference magnetization of the magnetic cells in the first subset comprises passing a first heating current pulse in said at least one first branch such as to heat the magnetic cells in the first subset; and
once said any the magnetic cells in the first subset are at the high threshold temperature, providing a first magnetic field generated by the apparatus; and
passing a second heating current pulse in said at least one second branch such as to heat the magnetic cells in the second subset; and
once said any the magnetic cells in the second subset are at the high threshold temperature, providing a second magnetic field generated by the apparatus.

11. The method according to claim 10 ,
wherein said providing a first magnetic field comprises moving the apparatus along the plane in a first direction to program the reference magnetization of the magnetic cells in the first subset in a first programmed direction; and
wherein said providing a second magnetic field comprises moving the apparatus along the plane in a second direction opposed to the first direction to program the reference magnetization of the magnetic cells in the second subset in a second programmed direction opposed to the first programmed direction.

12. The method according to claim 9 ,
wherein said providing a first magnetic field comprises annealing the magnetic device and providing an external magnetic field to switch the first magnetization of the plurality of magnetic cells in a first switched direction; and
wherein said providing a second magnetic field comprises moving the apparatus along the plane in a second direction opposed to the first direction to program the first magnetization of the magnetic cells in the second subset in a second programmed direction opposed to the first programmed direction.

Assignees

• Crocus Technology Sa

Inventors

• Alvarez-Herault Jeremy
• Lombard Lucien
• Stainer Quentin
• Childress Jeffrey

Classifications

• H01F7/0294

  Detection, inspection, magnetic treatment · CPC title

• H03K19/18

  using galvano-magnetic devices, e.g. Hall-effect devices · CPC title

• G11C11/161

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title

• G11C11/1675 Primary

  Writing or programming circuits or methods · CPC title

• H10N50/01

  Manufacture or treatment · CPC title