Rare earth thin film magnet and method for producing same

Patent metadata

Field	Value
Publication number	US-11072842-B2
Application number	US-201716080036-A
Country	US
Kind code	B2
Filing date	Mar 29, 2017
Priority date	Apr 15, 2016
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Provided is a rare earth thin film magnet having Nd, Fe and B as essential components, which is characterized in that a Nd—Fe—B base film is formed on a Si substrate having an oxide film formed on a surface thereof and has a composition in which the Nd content is higher than that of a stoichiometric composition and that a film (nano composite film) is formed on the base film and has a texture in which an α-Fe phase and Nd2Fe14B are alternately arranged and three-dimensionally dispersed. The rare earth thin film magnet provided is less susceptible to the occurrence of film separation and substrate breakage and exhibits favorable magnetic properties.

First claim

The invention claimed is:

1. A rare earth thin film magnet having Nd, Fe and B as essential components comprising:
a Nd—Fe—B base film on a Si substrate having an oxide film formed on a surface thereof;
the Nd—Fe—B base film has a composition in which a Nd content is higher than that of a stoichiometric composition of Nd 2 —Fe 14 —B;
nano composite film having a film thickness of 10 μm or more and 42 μm or less on the base film, and
the nano composite film has a texture in which an α-Fe phase and Nd 2 Fe 14 B are alternately arranged and three-dimensionally dispersed.

2. The rare earth thin film magnet according to claim 1 , wherein a film thickness of the base film is 0.5 μm or more.

3. The rare earth thin film magnet according to claim 2 , wherein a film thickness ratio of the base film relative to the nano composite film is 1/10 or less.

4. The rare earth thin film magnet according to claim 3 , wherein the oxide film on the surface of the Si substrate is a thermal oxide film.

5. The rare earth thin film magnet according to claim 4 , wherein the rare earth thin film magnet has a residual magnetization of 0.70 T or more.

6. The rare earth thin film magnet according to claim 5 , wherein the rare earth thin film magnet has a coercive force of 480 kA/m or more.

7. The rare earth thin film magnet according to claim 6 , wherein the rare earth thin film magnet has a maximum energy product (BH) max of 70 kJ/m 3 or more.

8. The rare earth thin film magnet according to claim 1 , wherein a film thickness ratio of the base film relative to the nano composite film is 1/10 or less.

9. The rare earth thin film magnet according to claim 1 , wherein the oxide film on the surface of the Si substrate is a thermal oxide film.

10. The rare earth thin film magnet according to claim 1 , wherein the rare earth thin film magnet has a residual magnetization of 0.70 T or more.

11. The rare earth thin film magnet according to claim 1 , wherein the rare earth thin film magnet has a coercive force of 480 kA/m or more.

12. The rare earth thin film magnet according to claim 1 , wherein the rare earth thin film magnet has a maximum energy product (BH) max of 70 kJ/m 3 or more.

13. A method of producing a rare earth thin film magnet, the method comprising:
forming an oxide film on a Si substrate;
forming a Nd—Fe—B base film having a composition in which a Nd content is higher than that of a stoichiometric composition of Nd 2 —Fe 14 —B on the Si substrate, as a first layer via pulsed laser deposition;
forming a nano composite film having a film thickness of 10 μm or more and 42 μm or less and having a texture in which an α-Fe phase and Nd 2 Fe 14 B are alternately arranged and three-dimensionally dispersed on the first layer, as a second layer via pulsed laser deposition; and
thereafter performing heat treatment thereto.

14. The method of producing a rare earth thin film magnet according to claim 13 , wherein deposition is performed using a target made from Nd X Fe 14 B (where X is a number that satisfies 2.1 to 2.7).

15. The method of producing a rare earth thin film magnet according to claim 14 , wherein a laser intensity density satisfies 1 J/cm 2 or more and less than 10 J/cm 2 in forming the base film as the first layer and satisfies 10 J/cm 2 or more and 1000 J/cm 2 or less in forming the nano composite film having a texture in which an α-Fe phase and Nd 2 Fe 14 B are alternately arranged as the second layer.

16. The method of producing a rare earth thin film magnet according to claim 15 , wherein the heat treatment is performed at 500° C. or higher and 800° C. or less.

17. The method of producing a rare earth thin film magnet according to claim 13 , wherein the heat treatment is performed at 500° C. or higher and 800° C. or less.

Assignees

• Jx Nippon Mining & Metals Corp

Inventors

• Nakano Masaki
• Fukunaga Hirotoshi
• Yanai Takeshi
• Sawatari Hironobu

Classifications

• C23C14/28

  by wave energy or particle radiation (C23C14/32 - C23C14/48 take precedence) · CPC title

• C23C14/58

  After-treatment · CPC title

• C23C28/04

  only coatings of inorganic non-metallic material · CPC title

• C22C38/005 Primary

  containing rare earths, i.e. Sc, Y, Lanthanides · CPC title

• C23C14/5806

  Thermal treatment · CPC title