Sensor

1. A sensor, comprising:

a nonmagnetic layer having a first surface configured to accept placement of a biological specimen and a second surface; and

a plurality of magnetic field sensors arranged along the second surface,

the second surface being between the first surface and the magnetic field sensors, each of the magnetic field sensors including

a first magnetic layer,

a second magnetic layer provided between the first magnetic layer and the nonmagnetic layer, and

an intermediate layer provided between the first magnetic layer and the second magnetic layer, the intermediate layer being nonmagnetic,

a distance between the first surface and the second magnetic layer being not more than a pitch of the magnetic field sensors,

wherein at least one of the magnetic field sensors is configured to output a sense signal corresponding to a pulse signal generated in the specimen and to detect a temporal change in a spatial distribution of the sense signal,

the magnetic field sensors include a first magnetic field sensor and a second magnetic field sensor,

a length of the first magnetic field sensor along a first extension direction aligned with the second surface is longer than a length of the first magnetic field sensor along a direction perpendicular to the first extension direction and aligned with the second surface,

a length of the second magnetic field sensor along a second extension direction is longer than a length of the second magnetic field sensor along a direction perpendicular to the second extension direction and aligned with the second surface, the second extension direction crossing the first extension direction and being aligned with the second surface,

the first magnetic field sensor is multiply provided,

the second magnetic field sensor is multiply provided,

one of the second magnetic field sensors is disposed between two of the first magnetic field sensors, and

one of the first magnetic field sensors is disposed between two of the second magnetic field sensors.

2. The sensor according to claim 1 , wherein the distance is 10 micrometers or less.

3. The sensor according to claim 1 , wherein

at least a portion of the magnetic field sensors is arranged along a first arrangement direction aligned with the second surface, and

at least a portion of the magnetic field sensors is arranged along a second arrangement direction, the second arrangement direction crossing the first arrangement direction and being aligned with the second surface.

4. The sensor according to claim 1 , wherein

at least a portion of the magnetic field sensors is arranged at a first pitch along a first arrangement direction, the first arrangement direction being aligned with the second surface, and

the first pitch is not less than 2 times and not more than 1000 times of the distance.

5. The sensor according to claim 4 , wherein

at least a portion of the magnetic field sensors is arranged at a second pitch along a second arrangement direction, the second arrangement direction crossing the first arrangement direction and being aligned with the second surface, and

the second pitch is not less than 2 times and not more than 1000 times of the distance.

6. The sensor according to claim 1 , wherein

at least a portion of the magnetic field sensors is arranged at a first pitch along a first arrangement direction, the first arrangement direction being aligned with the second surface, and

the first pitch is 14 μm or less.

7. The sensor according to claim 6 , wherein

at least a portion of the magnetic field sensors is arranged at a second pitch along a second arrangement direction, the second arrangement direction crossing the first arrangement direction and being aligned with the second surface, and

the second pitch is 14 μm or less.

8. The sensor according to claim 1 , wherein the specimen includes a living body.

9. The sensor according to claim 1 , further comprising a plurality of optical sensors arranged along the second surface,

at least one of the magnetic field sensors and at least one of the optical sensors being included in one of a plurality of sensing components.

10. The sensor according to claim 9 , wherein

a distance between the first surface and the at least one of the magnetic field sensors is shorter than a distance between the first surface and the at least one of the optical sensors.

11. The sensor according to claim 1 , further comprising a plurality of other sensors arranged along the second surface,

at least one of the magnetic field sensors and at least one of the other sensors being included in one of a plurality of sensing components,

one of the other sensors including at least one of a chemical sensor, a temperature sensor, or an electrical sensor.

12. The sensor according to claim 1 , further comprising a sensor circuit portion connected to at least one of the magnetic field sensors,

at least a portion of the magnetic field sensors being disposed between the nonmagnetic layer and at least a portion of the sensor circuit portion in a direction from the second surface toward the first surface.

13. The sensor according to claim 12 , wherein the sensor circuit portion includes at least a portion of a read circuit reading a state of the magnetic field sensors.

14. The sensor according to claim 1 , further comprising:

a selection circuit selecting the magnetic field sensors; and

a read circuit reading a state of the magnetic field sensors.

15. The sensor according to claim 14 , further comprising a current supply circuit supplying a current to the magnetic field sensors.

16. The sensor according to claim 1 , further comprising a difference circuit outputting a value made by differencing an output of one of the magnetic field sensors and an output of one other of the magnetic field sensors.

17. The sensor according to claim 1 , wherein the first surface is configured to directly contact with the specimen.

18. A sensor, comprising:

a nonmagnetic layer having a first surface and a second surface; and

a plurality of magnetic field sensors arranged along the second surface,

the second surface being between the first surface and the magnetic field sensors, each of the magnetic field sensors including

a first magnetic layer,

a second magnetic layer provided between the first magnetic layer and the nonmagnetic layer, and

an intermediate layer provided between the first magnetic layer and the second magnetic layer, the intermediate layer being nonmagnetic,

a distance between the first surface and the second magnetic layer being not more than a pitch of the magnetic field sensors

wherein

the magnetic field sensors include a first magnetic field sensor and a second magnetic field sensor,

a length of the first magnetic field sensor along a first extension direction aligned with the second surface is longer than a length of the first magnetic field sensor along a direction perpendicular to the first extension direction and aligned with the second surface, and

a length of the second magnetic field sensor along a second extension direction is longer than a length of the second magnetic field sensor along a direction perpendicular to the second extension direction and aligned with the second surface, the second extension direction crossing the first extension direction and being aligned with the second surface, and

the first magnetic field sensor and the second magnetic field sensor each being multiply provided, such that one of the second magnetic field sensors is disposed between two of the first magnetic field sensors, and one of the first magnetic field sensors is disposed between two of the second magnetic field sensors.