Spin hall magnetic sensor and method of measuring magnetoresistance using the same
A spin Hall magnetic sensor includes a plurality of magnetic thin film units including a magnetic layer stacked on a non-magnetic layer, and a plurality of non-magnetic substances disposed between the plurality of magnetic thin film units, The magnetic includes a Wheatstone bridge structure to observe a magnetic Hall resistance generated by a spin orbit torque (SOT).
1. A spin Hall magnetic sensor comprising:
a plurality of magnetic thin film units including a magnetic layer stacked on a non-magnetic layer; and
a plurality of non-magnetic substances disposed between the plurality of magnetic thin film units;
wherein the plurality of magnetic thin film units include:
a first magnetic thin film unit having a longitudinal direction having a constant angle with an input direction of a current;
a second magnetic thin film unit having a longitudinal direction disposed to form a constant angle with the longitudinal direction of the first magnetic thin film unit;
a third magnetic thin film unit having a longitudinal direction disposed parallel to the first magnetic thin film unit; and
a fourth magnetic thin film unit having a longitudinal direction disposed parallel to the second magnetic thin film unit.
2. The spin Hall magnetic sensor of claim 1 , wherein when the current is injected to the magnetic thin film unit, a spin current is generated in the non-magnetic layer, and a spin orbit torque (SOT) is generated on the magnetic layer.
3. The spin Hall magnetic sensor of claim 2 , wherein the plurality of non-magnetic substances include:
a first non-magnetic substance connecting the first magnetic thin film unit with the second magnetic thin film unit;
a second non-magnetic substance connecting the second magnetic thin film unit with the third magnetic thin film unit;
a third non-magnetic substance connecting the third magnetic thin film unit with the fourth magnetic thin film unit; and
a fourth non-magnetic substance connecting the fourth magnetic thin film unit with the first magnetic thin film unit.
4. The spin Hall magnetic sensor of claim 3 , wherein the longitudinal direction of the first magnetic thin film unit is formed at an angle of 45°±5° with an input direction of the current.
5. The spin Hall magnetic sensor of claim 3 , wherein the plurality of non-magnetic substances have a metal alloy structure in which the SOT is generated or a superlattice structure.
6. The spin Hall magnetic sensor of claim 3 , wherein each of the plurality of magnetic thin film units has three or more units connected to each other.
7. The spin Hall magnetic sensor of claim 6 , wherein when the number of units of each of the plurality of magnetic thin film units is 2n+1, where n is a natural number, n units among the units are non-magnetic substances.
8. A method of measuring a magnetic resistance using the spin Hall magnetic sensor of claim 3 , comprising:
applying the current to the spin Hall magnetic sensor;
measuring an output voltage V total of the spin Hall magnetic sensor; and
detecting a secondary harmonic signal voltage V DC,2nd from the output voltage.
9. The method of claim 8 , wherein the applying of the current to the spin Hall magnetic sensor includes applying an alternative current (AC) current.