Multi-state memory and multi-functional devices comprising magnetoplastic or magnetoelastic materials
Apparatus and methods are disclosed that enable writing data on, and reading data of, multi-state elements having greater than two states. The elements may be made of magnetoplastic and/or magnetoelastic materials, including, for example, magnetic shape-memory alloy or other materials that couple magnetic and crystallographic states. The writing process is preferably conducted through the application of a magnetic field and/or a mechanical action. The reading process is preferably conducted through atomic-force microscopy, magnetic-force microscopy, spin-polarized electrons, magneto-optical Kerr effect, optical interferometry or other methods, or other methods/effects. The multifunctionality (crystallographic, magnetic, and shape states each representing a functionality) of the multi-state elements allows for simultaneous operations including read&write, sense&indicate, and sense&control. Embodiments of the invention may be used, for example, for storing, modifying, and accessing data for device, sensor, actuator, logic and memory applications. Embodiments may be particularly effective for non-volatile memory or other read&write, sense&indicate, and/or sense&control functions in computer or other applications; such simultaneous operation of two (or more) of said multiple functionalities open new pathways for miniaturization of devices.
1. A logic or memory device comprising a magnetoplastic and/or magnetoelastic material having at least six states.
2. A device as in claim 1 which is a combined logic and memory device.
3. A device as in claim 1 wherein the memory is nonvolatile.
4. A device as in claim 2 wherein the memory is nonvolatile.
5. A device as in claim 1 wherein said states are shape states.
6. A device as in claim 1 wherein said states are magnetic states.
7. A device as in claim 1 , wherein said material is magnetic shape memory alloy.
8. A device as in claim 1 , wherein said material is selected from the group consisting of: Heusler shape-memory alloy, non-Heusler ferromagnetic shape-memory alloy, antiferromagnetic shape-memory alloy, non-shape-memory magnetoplastic alloy, Ni 2 MnGa, Dy, α-Fe, Co—Ni, τ-MnAl—C, L1 0 FePd, L1 0 CoPt, L1 0 FePt, Ni 2 MnGa, Co 2 NiGa, Ni 2 MnAl, Ni 2 FeGa, Fe 3 Pd, Fe—Pd—PT, γ-Mn—Fe—Cu, Ni 51 Mn 28 Ga 21 , Ni—Mn—Ga alloys, Ni—Mn—Ga ferromagnetic martensite, and combinations thereof.
9. A method of writing data on an element having more than two states, wherein the element comprises a magnetoplastic and/or magnetoelastic material having at least six states.
10. A method as in claim 9 , wherein the writing step comprises application of a magnetic field change.
11. A method as in claim 9 , wherein the writing step comprises application of a mechanical force.
12. A method as in claim 9 , wherein the states are shape states.
13. A method as in claim 9 wherein said states are magnetic states.
14. A method as in claim 9 , wherein said material is a magnetic shape memory alloy.
15. A method of reading data from an element having more than two states, wherein the element comprises a magnetoplastic and/or magnetoelastic material having at least six states.
16. A method as in claim 15 , wherein the writing step comprises application of a magnetic field change.
17. A method as in claim 15 , wherein the writing step comprises application of a mechanical force.
18. A method as in claim 15 , wherein the states are shape states.
19. A method as in claim 15 wherein said states are magnetic states.
20. A method as in claim 15 , wherein said material is a magnetic shape memory alloy.
21. A method as in claim 15 , wherein the reading step is conducted with atomic-force microscopy.
22. A method as in claim 15 , wherein the reading step is conducted with magnetic-force microscopy.
23. A method as in claim 15 , wherein the reading step is conducted with spin-polarized electrons.
24. A method as in claim 15 , wherein the reading step is conducted with magneto-optical Kerr-effect.
25. A method as in claim 15 , wherein the reading step is conducted with optical inferometry.
26. A method of writing data on, and reading data from, an element having more than two states, wherein the element comprises a magnetoplastic and/or magnetoelastic material having at least six crystallographic states.
27. A method of claim 26 wherein the writing step is selected from the group consisting of application of a magnetic field and application of mechanical force.
28. A method as in claim 26 wherein the reading step is selected from the group consisting of: atomic-force microscopy, magnetic-force microscopy, spin-polarized electrons, magneto-optical Kerr effect, and optical interferometry.
29. A method of combining memory and logic functionalities in a single element having more than two states, wherein the element comprises at least one magnetoplastic and/or magnetoelastic material having at least six states.
30. A method as in claim 29 , which combines read and write capabilities.
31. A method as in claim 29 , which combines sense and indicate capabilities.
32. A method as in claim 29 , which combines read and control capabilities.
33. A method as in claim 29 , wherein said at least six states are shape states.
34. A method as in claim 29 , wherein said at least six states are magnetic states.
35. A device as in claim 1 that is a data reading and writing device.
36. A device as in claim 1 that is a displacement and sensing device.
37. A device as in claim 1 that is a sensing and control device.
38. A device as in claim 1 that is a sensing and indicating device.