Magneto-resistance element capable of controlling the position and size of edge domain and the coercivity and magnetic memory

• US 6,765,824 B2
• Filed: 03/19/2003
• Issued: 07/20/2004
• Est. Priority Date: 03/29/2002
• Status: Expired due to Term

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ueda, Tomomasa, Kishi, Tatsuya, Takahashi, Shigeki, Saito, Yoshiaki, Nishiyama, Katsuya, Amano, Minoru
• Primary Examiner(s): Tran, Andrew Q.
• Application Number:
  US10/391,423
• Publication Number:
  US 20030185050A1
• Time in Patent Office: 489 Days
• Field of Search: 365/158, 365/173, 365/171, 365/132, 365/51
• US Class Current: 365/173
• CPC Class Codes: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: G11C 11/5607 using magnetic storage elements

Abstract

There is provided a magnetoresistance element in which a shape of a free ferromagnetic layer includes a first portion with a parallelogrammic contour, and second portions that protrude from a pair of opposite corners of the first portion respectively in a main direction parallel to a pair of opposite sides of the first portion, the shape is asymmetric with respect to a line that passes through a center of the first portion and is parallel to the main direction, and an axis of easy magnetization of the free ferromagnetic layer falls within a range defined by an acute angle that a first direction makes with a second direction, the first direction being substantially parallel to the main direction and the second direction being substantially parallel to the longest line segment that joins contours of the second portions.

Claims

1. A magnetoresistance element, comprising:

a first pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying a magnetic field;

a free ferromagnetic layer that faces the first pinned ferromagnetic layer and is capable of changing a magnetization direction thereof on applying the magnetic field; and

a first nonmagnetic layer intervening between the first pinned ferromagnetic layer and the free ferromagnetic layer,

wherein a shape of the free ferromagnetic layer that is viewed perpendicularly to a main surface thereof includes a first portion with a parallelogrammic contour and a pair of second portions that protrude from a pair of opposite corners of the first portion respectively in a main direction parallel to a pair of opposite sides of the first portion,

the shape of the free ferromagnetic layer is asymmetric with respect to a line that passes through a center of the first portion and is parallel to the main direction, and

an axis of easy magnetization of the free ferromagnetic layer falls within a range defined by an acute angle that a first direction makes with a second direction, the first direction being substantially parallel to the main direction and the second direction being substantially parallel to the longest line segment that joins contours of the second portions.

2. The element according to claim 1, wherein a direction of the magnetization of the first pinned ferromagnetic layer falls within the range defined by the acute angle.

3. The element according to claim 1, further comprising:

a second pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying the magnetic field; and

a second nonmagnetic layer intervening between the free ferromagnetic layer and the second pinned ferromagnetic layer.

4. The element according to claim 1, wherein the first portion is square or rectangle in shape.

5. The element according to claim 1, the second portions are rotation symmetrical with respect to a 2-fold axis that passes through the center of the first portion and is perpendicular to the main surface of the free ferromagnetic layer.

6. The element according to claim 1, wherein each of the second portions is triangle, semi-circle, square or rectangle in shape.

7. The element according to claim 1, wherein the shape of the first free ferromagnetic layer consists of the first and second portions.

8. A magnetic memory, comprising:

a word line;

a bit line intersecting the word line; and

a memory cell positioned at or near an intersection portion of the word and bit lines and including the element according to claim 1.

9. The memory according to claim 8, wherein a direction of the magnetization of the first pinned ferromagnetic layer falls within the range defined by the acute angle.

10. The memory according to claim 8, wherein the element further comprises:

a second pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying the magnetic field; and

a second nonmagnetic layer intervening between the free ferromagnetic layer and the second pinned ferromagnetic layer.

11. The memory according to claim 8, wherein the first portion is square or rectangle in shape.

12. The memory according to claim 8, the second portions are rotation symmetrical with respect to a 2-fold axis that passes through the center of the first portion and is perpendicular to the main surface of the free ferromagnetic layer.

13. The memory according to claim 8, wherein each of the second portions is triangle, semi-circle, square or rectangle in shape.

14. The memory according to claim 8, wherein the shape of the first free ferromagnetic layer consists of the first and second portions.

15. A magnetoresistance element, comprising:

a first pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying a magnetic field;

a free ferromagnetic layer that faces the first pinned ferromagnetic layer and is capable of changing a magnetization direction thereof on applying the magnetic field; and

a first nonmagnetic layer intervening between the first pinned ferromagnetic layer and the free ferromagnetic layer,

wherein a shape of the free ferromagnetic layer that is viewed perpendicularly to a main surface thereof includes a first portion with a quadrilateral contour whose first opposite sides are parallel to each other and whose second opposite sides are parallel to each other, and a pair of second portions that extend from a pair of opposite corner parts of the first portion in a main direction parallel to the second opposite sides respectively and whose maximum widths in a direction parallel to the first opposite sides are narrower than lengths of the first opposite sides,

the shape is asymmetric with respect to a line that passes through a center of the first portion and is parallel to the second opposite sides, and

an axis of easy magnetization of the free ferromagnetic layer falls within a range defined by an acute angle that a first direction makes with a second direction, the first direction being substantially parallel to the main direction and the second direction being substantially parallel to the longest line segment that joins contours of the second portions.

16. The element according to claim 15, wherein a direction of the magnetization of the first pinned ferromagnetic layer falls within the range defined by the acute angle.

17. The element according to claim 15, further comprising:

a second pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying the magnetic field; and

a second nonmagnetic layer intervening between the free ferromagnetic layer and the second pinned ferromagnetic layer.

18. A magnetic memory, comprising:

a word line;

a bit line intersecting the word line; and

a memory cell positioned at or near an intersection portion of the word and bit lines and including the element according to claim 15.

19. A magnetoresistance element, comprising:

a first pinned ferromagnetic layer that retains a magnetization direction thereof unchanged on applying a magnetic field;

a free ferromagnetic layer that faces the first pinned ferromagnetic layer and is capable of changing a magnetization direction thereof on applying the magnetic field; and

a first nonmagnetic layer intervening between the first pinned ferromagnetic layer and the free ferromagnetic layer,

wherein a shape of the free ferromagnetic layer that is viewed perpendicularly to a main surface thereof includes a first portion with a parallelogrammic contour, and a pair of second portions that protrude from a pair of opposite corners of the first portion respectively in a main direction parallel to a pair of opposite sides of the first portion,

the shape of the free ferromagnetic layer is asymmetric with respect to a line that passes through a center of the first portion and is parallel to the main direction, and

a direction of the magnetization of the first pinned ferromagnetic layer falls within a range defined by an acute angle that a first direction makes with a second direction, the first direction being substantially parallel to the main direction and the second direction being substantially parallel to the longest line segment that joins contours of the second portions.

20. A magnetic memory, comprising:

a word line;

a bit line intersecting the word line; and

a memory cell positioned at or near an intersection portion of the word and bit lines and including the element according to claim 19.