Magnetic sensor half-bridge based on inverse spin hall effect with reduced thermal drift
The present disclosure generally relates to a magnetic sensor half bridge circuit. The half bridge circuit comprises a bias source connected to a first leg and a second leg. The first leg comprises one or more first spin-orbit torque (SOT) structures connected in series, each first SOT structure comprising a first ferromagnetic (FM) layer disposed on a first SOT layer. The first SOT layer has a first end connected to ground and a second end connected to a first voltage sensor. The second leg comprises one or more second SOT structures connected in series, each second SOT structure comprising a second FM layer disposed on a second SOT layer. The second SOT layer has a first end connected to a second voltage sensor and a second end connected to a ground. The first voltage sensor is disposed adjacent to the second voltage sensor.
1. A half bridge circuit, comprising:
a first spin-orbit torque (SOT) layer having a first end and a second end opposite the first end;
a first ferromagnetic (FM) layer disposed on the first SOT layer;
a first ground connected to the first end of the first SOT layer;
a first voltage sensor connected to the second end of the first SOT layer;
a bias source connected to the first FM layer;
a second SOT layer having a first end and a second end opposite the first end;
a second FM layer disposed on the second SOT layer, the second FM layer being connected to the bias source;
a second ground connected to the second end of the second SOT layer; and
a second voltage sensor connected to the first end of the second SOT layer.
2. The half bridge circuit of claim 1 , wherein the first voltage sensor is disposed adjacent to the second voltage sensor.
3. The half bridge circuit of claim 1 , wherein a ratio of a width of the first FM layer to a height of the first FM layer is greater than or equal to 3, and wherein a ratio of a width of the second FM layer to a height of the second FM layer is greater than or equal to 3.
4. The half bridge circuit of claim 1 , further comprising:
a first biasing layer disposed adjacent to the first FM layer over the first end of the first SOT layer;
a second biasing layer disposed adjacent to the first FM layer over the second end of the first SOT layer;
a third biasing layer disposed adjacent to the second FM layer over the first end of the second SOT layer; and
a fourth biasing layer disposed adjacent to the second FM layer over the second end of the second SOT layer.
5. The half bridge circuit of claim 1 , further comprising:
a third FM layer disposed below the first SOT layer; and
a fourth FM layer disposed below the second SOT layer.
6. The half bridge circuit of claim 1 , wherein the first FM layer and the second FM layer are each individually rectangular or elliptical in shape.
7. A magnetic sensor comprising the half bridge circuit of claim 1 .
8. A half bridge circuit, comprising:
a bias source;
a first leg connected to the bias source, the first leg comprising one or more first spin-orbit torque (SOT) structures, each first SOT structure comprising:
a first SOT layer having a first end and a second end opposite the first end;
a first ferromagnetic (FM) layer disposed on the first SOT layer;
a first ground connected to the first end of the first SOT layer; and
a first voltage sensor connected to the second end of the first SOT layer; and
a second leg connected to the bias source, the second leg comprising one or more second SOT structures, each second SOT structure comprising:
a second SOT layer having a first end and a second end opposite the first end;
a second FM layer disposed on the second SOT layer;
a second ground connected to the second end of the second SOT layer; and
a second voltage sensor connected to the first end of the second SOT layer.
9. The half bridge circuit of claim 8 , wherein the first leg comprises a plurality of first SOT structures connected in series, and the second leg comprises a plurality of second SOT structures connected in series.
10. The half bridge circuit of claim 8 , wherein the bias source is connected to the first FM layer and to the second FM layer.
11. The half bridge circuit of claim 8 , wherein the first SOT layer and the second SOT layer each individually comprises BiSb or YPtSb.
12. The half bridge circuit of claim 8 , wherein the second end of the first SOT layer is disposed adjacent to the first end of the second SOT layer.
13. The half bridge circuit of claim 8 , wherein the first FM layer is disposed between a first biasing layer and a second biasing layer, and wherein the second FM layer is disposed between a third biasing layer and a fourth biasing layer.
14. A magnetic sensor comprising the half bridge circuit of claim 8 .
15. A half bridge circuit, comprising:
a bias source;
a first leg connected to the bias source, the first leg comprising one or more first spin-orbit torque (SOT) structures connected in series, each first SOT structure comprising:
a first SOT layer having a first end and a second end opposite the first end;
a first ferromagnetic (FM) layer disposed on the first SOT layer;
a second FM layer disposed below the first SOT layer;
a first ground connected to the first end of the first SOT layer; and
a first voltage sensor connected to the second end of the first SOT layer; and
a second leg connected to the bias source, the second leg comprising one or more second SOT structures connected in series, each second SOT structure comprising:
a second SOT layer having a first end and a second end opposite the first end, wherein the first end of the second SOT layer is disposed adjacent to the second end of the first SOT layer;
a third FM layer disposed on the second SOT layer;
a fourth FM layer disposed below the second SOT layer;
a second ground connected to the second end of the second SOT layer; and
a second voltage sensor connected to the first end of the second SOT layer.
16. The half bridge circuit of claim 15 , wherein:
a ratio of a width of the first FM layer to a height of the first FM layer is greater than or equal to 3;
a ratio of a width of the second FM layer to a height of the second FM layer is greater than or equal to 3;
a ratio of a width of the third FM layer to a height of the third FM layer is greater than or equal to 3; and
a ratio of a width of the fourth FM layer to a height of the fourth FM layer is greater than or equal to 3.
17. The half bridge circuit of claim 15 , wherein:
the first FM layer is disposed between a first biasing layer and a second biasing layer;
the second FM layer is disposed between a third biasing layer and a fourth biasing layer;
the third FM layer is disposed between a fifth biasing layer and a sixth biasing layer; and
the fourth FM layer is disposed between a seventh biasing layer and an eighth biasing layer.
18. The half bridge circuit of claim 17 , wherein the first, second, third, fourth, fifth, and sixth biasing layers are hard biasing layer.
19. The half bridge circuit of claim 17 , wherein the first, second, third, fourth, fifth, and sixth biasing layers are soft biasing layer.
20. The half bridge circuit of claim 15 , wherein:
a width of the first FM layer is greater than a height of the first FM layer;
a width of the second FM layer is greater than a height of the second FM layer;
a width of the third FM layer is greater than a height of the third FM layer; and
a width of the fourth FM layer is greater than a height of the fourth FM layer.
21. A magnetic sensor comprising the half bridge circuit of claim 15 .