Devices for determining a number of rotations of a magnetic field
A device includes a magnetic layer and a guiding structure arranged over the magnetic layer and configured to sequentially transfer a skyrmion in the magnetic layer along a transfer pattern in response to a rotating magnetic field. The device further includes a plurality of magnetoresistive elements arranged along the transfer pattern and configured to detect a position of the skyrmion in the transfer pattern. The device is configured to determine a number of rotations of the rotating magnetic field based on the detected position of the skyrmion in the transfer pattern.
1 . A device, comprising:
a magnetic layer;
a guiding structure arranged over the magnetic layer and configured to sequentially transfer a skyrmion in the magnetic layer along a transfer pattern in response to a rotating magnetic field; and
a plurality of magnetoresistive elements arranged along the transfer pattern and configured to detect a position of the skyrmion in the transfer pattern,
wherein the device is configured to determine a number of rotations of the rotating magnetic field based on the position of the skyrmion in the transfer pattern.
2 . The device of claim 1 , wherein:
a transfer of the skyrmion in the magnetic layer along the transfer pattern is effected by a magnetization of the guiding structure, and
the magnetization of the guiding structure is generated by the rotating magnetic field.
3 . The device of claim 1 , wherein a transfer of the skyrmion in the magnetic layer along the transfer pattern is independent of any power supply.
4 . The device of claim 1 , wherein the guiding structure comprises:
a plurality of T-shaped soft magnetic components, and
a plurality of I-shaped soft magnetic components, wherein the T-shaped components and the I-shaped components are arranged alternately.
5 . The device of claim 4 , wherein a magnetoresistive element is arranged at each T-shaped component.
6 . The device of claim 4 , wherein a first respective magnetoresistive element is arranged at each T-shaped component and a second respective magnetoresistive element is arranged at each I-shaped component.
7 . The device of claim 1 , wherein the transfer pattern forms a closed loop.
8 . The device of claim 1 , wherein:
during N1 consecutive rotations of the rotating magnetic field, the skyrmion is sequentially transferred along N1 positions on the transfer pattern, wherein N1 is a first integer, and
after the N1 consecutive rotations of the rotating magnetic field, the skyrmion again reaches a same position on the transfer pattern.
9 . The device of claim 8 , wherein:
N1 magnetoresistive elements of the plurality of magnetoresistive elements are arranged at the N1 positions, respectively, and
the device is configured to determine the number of rotations of the rotating magnetic field based on N1 measurement values provided by the N1 magnetoresistive elements.
10 . The device of claim 9 , further comprising:
a further guiding structure configured to sequentially transfer a further skyrmion in the magnetic layer along a further transfer pattern in response to the rotating magnetic field;
a further plurality of magnetoresistive elements arranged along the further transfer pattern and configured to detect a position of the further skyrmion in the further transfer pattern,
wherein the device is configured to determine the number of rotations of the rotating magnetic field based on the position of the further skyrmion in the further transfer pattern.
11 . The device of claim 10 , wherein:
the further transfer pattern forms a further closed loop,
during N2 consecutive rotations of the rotating magnetic field, the further skyrmion is sequentially transferred along N2 positions on the further closed loop, wherein N2 is a second integer,
after the N2 consecutive rotations of the rotating magnetic field, the further skyrmion again reaches a same position on the further closed loop, and
N1 and N2 are coprime numbers.
12 . The device of claim 1 , wherein a magnetoresistive element of the plurality of magnetoresistive elements comprises:
a free layer, wherein the free layer is at least partially formed by the magnetic layer,
an intermediate layer arranged over the magnetic layer, wherein the intermediate layer comprises a spacer layer or a tunnel barrier layer, and
a reference layer arranged over the intermediate layer.
13 . The device of claim 12 , wherein the magnetoresistive element of the plurality of magnetoresistive elements further comprises:
a further free layer arranged between the magnetic layer and the intermediate layer, wherein the further free layer is sensitive to magnetic fields in a direction perpendicular to the further free layer.
14 . The device of claim 13 , wherein at least one of the intermediate layer, the reference layer, or the further free layer comprises a sputtered film.
15 . The device of claim 1 , wherein the magnetic layer, the guiding structure, and the plurality of magnetoresistive elements are integrated in a single semiconductor chip.
16 . The device of claim 1 , wherein:
the device is configured to generate a bias magnetic field in a direction perpendicular to the magnetic layer, and
a magnetization of the skyrmion is anti-parallel to a direction of the bias magnetic field.
17 . The device of claim 1 , further comprising:
a component configured to generate the skyrmion and feed the skyrmion into the transfer pattern, wherein the component comprises at least one of a magnetoresistive element or a conductive loop.
18 . The device of claim 1 , wherein the device is configured to remove one or multiple skyrmions from the magnetic layer based on a spin orbit torque effect.
19 . The device of claim 1 , wherein the magnetic layer and a rotation plane of the magnetic field are arranged parallel to each other.
20 . The device of claim 1 , wherein each magnetoresistive element of the plurality of magnetoresistive elements is connected with a top contact and a bottom contact.
21 . The device of claim 1 , wherein each magnetoresistive element of the plurality of magnetoresistive elements is connected with two bottom contacts.
22 . A method for fabricating a device, wherein the method comprises:
providing a magnetic layer;
arranging a guiding structure over the magnetic layer, wherein the guiding structure is configured to sequentially transfer a skyrmion in the magnetic layer along a transfer pattern in response to a rotating magnetic field; and
arranging a plurality of magnetoresistive elements along the transfer pattern, wherein the magnetoresistive elements are configured to detect a position of the skyrmion in the transfer pattern,
wherein the fabricated device is configured to determine a number of rotations of the rotating magnetic field based on the position of the skyrmion in the transfer pattern.