Systems And Methods For Making Radially Anisotropic Thin-Film Magnetic Torroidal Cores, And Radially Anisotropic Cores Having Radial Anisotropy, And Inductors Having Radially Anisotropic Cores

• US 20140240074A1
• Filed: 09/24/2012
• Published: 08/28/2014
• Est. Priority Date: 09/22/2011
• Status: Active Grant

• Current Assignee: The Trustees of Dartmounth College (Dartmouth College)
• Original Assignee: Trustees of Dartmouth College
• Inventors: Sullivan, Charles R., Qui, Jizheng
• Granted Patent: US 9,659,706 B2
• Time in Patent Office: Days
• US Class Current: 336/211
• CPC Class Codes: C23C 16/458 characterised by the method used for supporting substrates in the reaction chamber
• CPC Class Codes: C23C 16/4583 the substrate being supported substantially horizontally
• CPC Class Codes: C23C 16/4584 the substrate being rotated
• CPC Class Codes: G11C 19/08 using thin films in plane structure
• CPC Class Codes: G11C 19/0808 using magnetic domain propagation
• CPC Class Codes: G11C 19/0816 using a rotating or alternating coplanar magnetic field
• CPC Class Codes: H01F 3/02 made from sheets
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: H01F 41/18 by cathode sputtering
• CPC Class Codes: H01F 7/02 Permanent magnets [PM]
• CPC Class Codes: H01F 7/0273 Magnetic circuits with PM for magnetic field generation
• CPC Class Codes: Y10T 29/49075 including permanent magnet or core
• CPC Class Codes: Y10T 29/49076 From comminuted material
• CPC Class Codes: Y10T 29/49078 Laminated

Abstract

A radially anisotropic toroidal magnetic core is fabricated by a method including providing apparatus having a first magnet for providing a radial magnetic field extending across a cavity from an axial spindle to a surrounding second magnetic element, placing a substrate in the cavity, the substrate having a hole fitting around the head of the spindle; and sputter-depositing a film of ferromagnetic material onto the substrate. An alternative fabrication uses a similar fixture to impose magnetic anisotropy by annealing a previously-formed toroidal core. A particular fixture adapted for deposition by electroplating or for applying anisotropy by annealing pre-formed cores applies magnetic fields symmetrically from above and below the cores. Also described are the radially anisotropic core produced by the method, and an inductor having a coil wound on the radially anisotropic core.

Claims

1. A method of fabricating a core having a radial aniosotropy, the method comprising

providing an apparatus for providing a radial magnetic field comprising

a first magnet for providing the magnetic field, the field extending from an axial spindle of the apparatus to a surrounding second magnetic element,

placing a substrate in a region subject to magnetic fields extending from the spindle to the second magnetic element;

and

depositing a film of aniosotropic ferromagnetic material onto the substrate.

2. The method of claim 1 wherein the apparatus for providing a radial magnetic field comprises the spindle formed of magnetic material, the spindle being magnetically coupled to a first pole of the first magnet, the spindle having a head opposite the first magnet, the head having a diameter greater than a diameter of an intermediate section of the spindle disposed between the magnet and the head;

and

wherein the second magnetic element is coupled to a second pole of the first magnet; and

a thermally conductive, nonmagnetic, insert disposed between the intermediate section of the spindle and the second magnetic element.

3. The method of claim 1 wherein the apparatus for providing a radial magnetic field has the spindle formed of magnetic material, the spindle being magnetically coupled to a first pole of the first magnet, the first magnet is a permanent magnet, the spindle having a head opposite the first magnet, the head having a diameter greater than a diameter of an intermediate section of the spindle disposed between the first magnet and the head, a second permanent magnet magnetically coupled to a second pole of the first magnet, and wherein the second magnetic element is coupled to a second pole of the second magnet.

4. The method of claim 3 wherein the first magnet is coupled to the second magnet by a magnetic plate.

5. The method of claim 4 wherein the magnetic plate is an iron plate.

6. The method of claim 1 wherein the apparatus for providing a radial magnetic field has the spindle formed of magnetic material, the spindle being magnetically coupled to a first pole of the first magnet, the spindle having a head opposite the first magnet, the head having a diameter greater than a diameter of an intermediate section of the spindle disposed between the magnet and the head, a second magnet magnetically coupled to a second pole of the first magnet, and wherein the second magnetic element is coupled to a second pole of the second magnet, and wherein at least one magnet is an electromagnet.

7. The method of claim 2 where the film of ferromagnetic material comprises a ferromagnetic metal-nonmetal granular material.

8. The method of claim 7 wherein the metal-nonmetal granular material is Cobalt-Zirconium-Oxide (Co—

Zr—

O).

9. The method of claim 2 where the film of ferromagnetic material comprises a ferromagnetic metal alloy.

10. The method of claim 9 wherein the metal alloy comprises primarily nickel-iron.

11. The method of claim 2 where the first magnet is a permanent magnet.

12. The method of claim 2 wherein the first magnet is an electromagnet.

13. The method of claim 2 wherein the film of ferromagnetic material comprises an amorphous metal alloy film.

14. Apparatus for fabricating a core having radial anisotropy comprising:

a magnetic orientation fixture comprising at least a first magnet for providing a radial magnetic field extending from an axial spindle to a surrounding second magnetic element, the axial spindle and the surrounding second magnetic element defining a location for placement of cores therebetween; and

deposition apparatus configured for deposition of films of ferromagnetic material;

wherein the magnetic orientation fixture is configured for placement in a deposition chamber of the deposition apparatus.

15. The apparatus of claim 14 wherein the spindle is formed of magnetic material, the spindle being magnetically coupled to a first pole of the first magnet, the spindle having a head opposite the first magnet, the head having a diameter greater than a diameter of an intermediate section of the spindle disposed between the magnet and the head;

and wherein the second magnetic element is coupled to a second pole of the first magnet; and

a thermally conductive, nonmagnetic, insert disposed between the intermediate section of the spindle and the second magnetic element.

16. The apparatus of claim 14 has the spindle formed of magnetic material, the spindle being magnetically coupled to a first pole of the first magnet, the spindle having a head opposite the first magnet, the head having a diameter greater than a diameter of an intermediate section of the spindle disposed between the magnet and the head, a second magnet magnetically coupled to a second pole of the first magnet, and wherein the second magnetic element is coupled to a second pole of the second magnet.

17. The apparatus of claim 16 wherein the first magnet is coupled to the second magnet by a magnetic plate.

19. The apparatus of claim 14 where the deposition apparatus is sputter deposition apparatus is configured to deposit a film of a ferromagnetic metal-nonmetal granular material.

20. The apparatus of claim 19 wherein the metal-nonmetal granular material is Co—

Zr-Oxide.

21. The apparatus of claim 14 where the film of ferromagnetic material comprises a ferromagnetic metal alloy.

22. The apparatus of claim 21 wherein the metal alloy comprises primarily nickel-iron.

23. The apparatus of claim 14 where the first magnet is a permanent magnet.

18. (canceled)

24. A radially anisotropic toroidal magnetic core comprising a radially anisotropic film of a ferromagnetic metal-nonmetal granular material comprising Co—

Zr-Oxide.

27. The core of claim 24 where the film of ferromagnetic material further comprises a ferromagnetic metal alloy.

28. The core of claim 24, wherein the film of ferromagnetic material further comprises an amorphous metal film.

30. An inductor comprising a coil surrounding at least a portion of the radially anisotropic core of claim 27.

25-26. -26. (canceled)

29. A radially anisotropic toroidal magnetic core comprising a film of ferromagnetic material comprising a magnetic material selected from the group consisting of Co—

Zr—

O, Fe—

Hf—

O, Ni—

Fe, Co—

Ni—

Fe, Co—

Zr—

Ta CoZrNb, FeCoBC, FeHfO, CoFeHfO, FeZrO, Fe₅₉Co₂₀B₁₄N₇, FeBN, CoMgF₂, CoZrO, CoHfTaPd, CoZrTa, permalloy, Ni₄₅Fe₅₅, NiFeMo, Co₆₅Ni₁₂Fe₂₃, and CoFeP

35. An inductor comprising a coil surrounding at least a portion of the radially anisotropic core of claim 29.

31. A method of fabricating a core having a radial aniosotropy, the method comprising

Fabricating a core of anisotropic material;

Providing a fixture comprising a first magnet for providing a radial magnetic field extending from an axial spindle of the fixture to a surrounding second magnetic element, a magnetic field extending from the axial spindle to the second magnetic element;

placing the core in a region subject to magnetic fields extending from the spindle to the second magnetic element; and

heating the core above a transition temperature of the core to cause the anisotropic magnetic material of the core to become radially anisotropic.

32. The method of claim 31 where the fixture further comprises a third magnet for providing a radial magnetic field extending from a second axial magnetic element of the fixture to a surrounding fourth magnetic element, a magnetic field extending from the second axial magnetic element to the fourth magnetic element;

Where the third magnet is opposite the first magnet, and the second magnetic element opposite the fourth magnetic element;

Wherein the core is placed in a region subject to magnetic fields extending from the second spindle to the fourth magnetic element during the step of heating the core.

33. A method of fabricating a core having a radial aniosotropy, the method comprising

Providing a fixture comprising a first magnet for providing a radial magnetic field extending from an axial magnetic element of the fixture to a surrounding second magnetic element;

The fixture further comprising at least a second magnet for providing a radial magnetic field extending from a third magnetic element to a surrounding fourth magnetic element;

placing a substrate in a region subject to magnetic fields extending from the first and third magnetic elements to the second and fourth magnetic elements; and

electroplating core magnetic material onto the substrate to form a radially anisotropic core.

34. The method of claim 33 further comprising simultaneously electroplating core magnetic material onto a second core, the second core in a region subject to magnetic fields extending from a fifth and seventh magnetic element to a sixth and eighth magnetic element, the first magnet providing magnetic fields to the fifth and sixth magnetic elements, and the second magnet providing magnetic fields to the seventh and eighth magnetic elements.