US 11,874,345 B2
Magnetic sensor and method of manufacturing such, and magnetic detection device and magnetic detection system
Keisuke Takasugi, Tokyo (JP)
Assigned to TDK Corporation, Tokyo (JP)
Filed by TDK Corporation, Tokyo (JP)
Filed on Oct. 23, 2020, as Appl. No. 17/078,315.
Claims priority of application No. 2019-193629 (JP), filed on Oct. 24, 2019.
Prior Publication US 2021/0123990 A1, Apr. 29, 2021
Int. Cl. G01R 33/09 (2006.01); G01N 33/543 (2006.01); H10N 50/85 (2023.01)
CPC G01R 33/093 (2013.01) [G01N 33/54326 (2013.01); H10N 50/85 (2023.02)] 14 Claims
OG exemplary drawing
 
1. A magnetic sensor used to detect a detection target substance in a sample, the magnetic sensor comprising:
a substrate having a first surface and a second surface, which is opposite the first surface;
a magnetoresistive effect element provided on the first surface of the substrate, wherein the resistance of the magnetoresistive effect element changes in accordance with an input magnetic field; and
a protective layer that covers the magnetoresistive effect element;
wherein a surface of the protective layer, which is positioned on top of the magnetoresistive effect element, has a prescribed surface roughness, and
a lower limit of a mean roughness Ra of the surface of the protective layer is 0.1 nm, and an upper limit of the mean roughness Ra is half a thickness of the protective layer on the magnetoresistive effect element.