What is claimed is:
1. A method for cutting a rare earth alloy comprising the steps of: cutting an object to be machined using a cutting wire while supplying slurry comprising dispersed abrasive grains between said cutting wire and said object,
wherein said wire is driven with a drive member, at least a wire contact face of said drive member being composed of an organic polymer material, and
wherein said cutting is carried out while a tension in a range between 14.7 N and 39.2 N is applied to said wire.
2. A method for cutting a rare earth alloy comprising the steps of: cutting an object to be machined using a cutting wire while supplying slurry comprising dispersed abrasive grains between said cutting wire and said object,
wherein said wire is driven with a drive member, at least a wire contact face of said drive member being composed of an organic polymer material, and
wherein the temperature of said slurry is controlled to fall within a predetermined range.
3. The method according to claim 2, further comprising the steps of:
collecting said slurry containing sludge produced during said cutting of said object to remove the sludge from said slurry; and
performing temperature control for said slurry from which said sludge is removed.
4. The method according to either claim 1 or 2, wherein said object is a R-Fe-B rare earth sintered magnet, where R is a rare earth element including Y.
5. The method according to either claim 1 or 2, wherein the viscosity of said slurry at 25 C. is in a range from 92 to 175 mPasec.
6. The method according to either claim 1 or 2, wherein sludge is collected from said slurry with a magnetic separator.
7. The method according to claim 6, wherein said magnetic separator generates a magnetic field of 0.3 tesla or more in a region where the sludge is collected.
8. The method according to either claim 1 or 2, wherein said rare earth alloy is cut while being lowered from a position above said wire to a position below said wire.
9. The method according to either claim 1 or 2, wherein said rare earth alloy is divided into a plurality of blocks that are secured together, and at least part of said slurry is supplied through gaps between said blocks.
10. The method according to either claim 1 or 2, wherein means for supplying said slurry to said wire is disposed at a position upstream of a wire running direction with respect to the object to be machined.
11. The method according to either claim 1 or 2, wherein a slurry supply aperture is adapted to supply slurry to said wire at a position upstream of a wire running direction with respect to the object to be machined.
12. The method according to either claim 1 or 2, wherein said drive member is a roller made of ester-type urethane rubber.
13. A method for manufacturing rare earth alloy plates, comprising the steps of:
producing an ingot of a rare earth alloy; and
separating a plurality of rare earth alloy plates from the ingot using the method for cutting a rare earth alloy according to either claim 1 or 2.
14. A method for manufacturing rare earth magnets comprising the steps of:
producing a rare earth magnet by compacting and sintering rare earth alloy powder; and
separating a plurality of magnets from said rare earth magnet by the method for cutting a rare earth alloy according to either claim 1 or 2.
15. A voice coil motor comprising the rare earth magnet manufactured by the method according to claim 14.
16. A voice coil motor according to claim 15, wherein the thickness of the rare earth magnet is in a range from 0.5 to 3.0 mm.
17. An apparatus for cutting a rare earth alloy, wherein an object to be machined is cut with a cutting wire while slurry containing dispersed abrasive grains is supplied between said wire and said object, the apparatus comprising:
means for supplying said slurry between said wire and said object;
a drive member for driving said wire, at least a wire contact face of said drive member being composed of an organic polymer material; and
means for applying to said wire a tension in a range between 14.7 N and 39.2 N.
18. An apparatus for cutting a rare earth alloy wherein an object to be machined is cut with a cutting wire while slurry containing dispersed abrasive grains is supplied between said wire and said object, the apparatus comprising:
means for supplying said slurry between said wire and said object;
a drive member for driving said wire, at least a wire contact face of said drive member being composed of an organic polymer material;
a temperature detector for detecting the temperature of said slurry; and
a cooling device for cooling said slurry to control the temperature of said slurry to fall within a predetermined range.
19. The apparatus according to claim 18, further comprising means for heating said slurry.
20. The apparatus according to any of claims 17 to 19, further comprising a magnetic separator for separating sludge of the rare earth alloy produced during said cutting of the rare earth alloy from said slurry by use of a magnetic field.
21. The apparatus according to claim 20, wherein said magnetic separator generates a magnetic field of 0.3 tesla or more in a region where the sludge is collected.
22. The apparatus according to any of claims 17 to 19, wherein the viscosity of said slurry at 25 C. is in a range from 92 to 175 mPasec.
23. An apparatus for cutting a rare earth alloy, wherein an object to be machined is cut with a cutting wire while slurry containing dispersed abrasive grains is supplied between said wire and said object, the apparatus comprising:
at least one slurry supply aperture for supplying said slurry between said wire and said object;
a drive member for driving said wire, at least a wire contact face of said drive member being composed of an organic polymer material; and
a wire tensioner for applying to said wire a tension in a range between 14.7 N and 39.2 N.
24. An apparatus for cutting a rare earth alloy wherein an object to be machined is cut with a cutting wire while slurry containing dispersed abrasive grains is supplied between said wire and said object, the apparatus comprising:
at least one slurry supply aperture for supplying slurry between said wire and said object;
a drive member for driving said wire, at least a wire contact face of said drive member being composed of an organic polymer material;
a temperature detector for detecting the temperature of said slurry; and
a cooling device for cooling said slurry to control the temperature of said slurry to fall within a predetermined range.
25. The apparatus according to claim 24, further comprising a slurry heater.
26. The apparatus according to any of claims 23 to 25, further comprising a magnetic separator for separating sludge of the rare earth alloy produced during said cutting of the rare earth alloy from said slurry by use of a magnetic field.
27. The apparatus according to claim 26, wherein said magnetic separator generates a magnetic field of 0.3 tesla or more in a region where the sludge is collected.
28. The apparatus according to any of claims 23 to 25, wherein the viscosity of said slurry at 25 C. is in a range from 92 to 175 mPasec.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A memristive device, comprising:
a first electrode;
a second electrode crossing the first electrode at a non-zero angle;
an active region disposed between the first and second electrodes; and
a continuous gradient of a single type of defect formed in the active region, the continuous gradient including an increasing or decreasing concentration of the single type of defect along a thickness of the entire active region.
2. The memristive device as defined in claim 1 wherein the active region is selected from the group consisting of an oxide, a nitride, and a sulfide, and wherein the single type of defect is respectively selected from the group consisting of oxygen vacancies, nitrogen vacancies, and sulfur vacancies.
3. The memristive device as defined in claim 1 wherein the active region thickness ranges from about 2 nm to about 100 nm.
4. The memristive device as defined in claim 1 wherein when the memristive device is in an OFF state, a portion of the active region is substantially void of the single type of defect.
5. The memristive device as defined in claim 4 wherein i) the portion is adjacent to the first electrode, or ii) the portion is adjacent to the second electrode.
6. A method for making a memristive device, the method comprising:
forming an active region including multiple metal oxide layers, multiple metal nitride layers, or multiple metal sulfide layers, wherein a cycle to form one of the multiple metal oxide layers, one of the multiple metal nitride layers, or one of the multiple metal sulfide layers includes:
exposing a surface of an electrode to a pulse of a metal precursor;
exposing the surface to one of an oxygen precursor, a nitride precursor, or a sulfide precursor; and
controlling a temperature at which the exposing steps take place, thereby controlling a concentration of a single type of defect throughout a thickness of the one metal oxide layer, the one metal nitride layer, or the one metal sulfide layer; and
varying the temperature continuously at each cycle to form a continuous gradient of the single type of defect in the active region, the continuous gradient including an increasing or decreasing concentration of the single type of defect along a thickness of the entire active region.
7. The method as defined in claim 6 wherein the surface is exposed to an oxygen precursor selected from the group consisting of water, oxygen plasma, and ozone, or a nitrogen precursor selected from the group consisting of NH3 and N2H2, or a sulfide precursor of H2SN2.
8. The method as defined in claim 6, further comprising engineering the continuous gradient such that the memristive device is operable with a predetermined switching polarity.
9. The method as defined in claim 6, further comprising engineering the continuous gradient such that the active region exhibits a predetermined resistivity.
10. The method as defined in claim 6 wherein the exposing steps are accomplished via atomic layer deposition.
11. A method for making a memristive device, the method comprising:
exposing a surface of an electrode to a pulse of a metal precursor;
exposing the surface to one of an oxygen precursor, a nitride precursor, or a sulfide precursor, thereby forming one of a metal oxide layer, a metal nitride layer, or a metal sulfide layer having a predetermined amount of defects therein; and
controlling a temperature at which the exposing steps take place, thereby controlling a concentration of the defects throughout a thickness of the one of the metal oxide layer, the metal nitride layer, or the metal sulfide layer;
wherein the metal precursor is a titanium precursor having a chemical formula of C16H40N4Ti.
12. A crossbar array, comprising:
a first set of at least two parallel electrodes;
a second set of at least two parallel electrodes crossing the first set of at least two parallel electrodes at a non-zero angle;
a junction formed at each point where one of the at least two parallel electrodes in the first set crosses one of the at least two parallel electrodes in the second set;
an active region disposed in each junction; and
a continuous gradient of a single type of defect formed in each of the active regions, the continuous gradient including an increasing or decreasing concentration of the single type of defect along a thickness of the entire active region.
13. The crossbar array as defined in claim 12 wherein the continuous gradient in the active region formed in one of the junctions is different from the continuous gradient in the active region formed in another of the junctions.
14. The crossbar array as defined in claim 12 wherein the continuous gradient in each of the active regions is the same.
15. The crossbar array as defined in claim 12 wherein each active region is selected from the group consisting of an oxide, a nitride, and a sulfide, and wherein the single type of defect is respectively selected from the group consisting of oxygen vacancies, nitrogen vacancies, and sulfur vacancies.