US 12,272,476 B2
Photodetection element and receiver
Tomohito Mizuno, Tokyo (JP); Hideaki Fukuzawa, Tokyo (JP); and Tetsuya Shibata, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Oct. 22, 2021, as Appl. No. 17/508,570.
Claims priority of application No. 2020-178887 (JP), filed on Oct. 26, 2020; and application No. 2021-129257 (JP), filed on Aug. 5, 2021.
Prior Publication US 2022/0068537 A1, Mar. 3, 2022
Int. Cl. H01F 10/32 (2006.01); G01R 33/09 (2006.01); G11B 5/39 (2006.01); H10N 50/10 (2023.01); H10N 50/85 (2023.01)
CPC H01F 10/3254 (2013.01) [G01R 33/093 (2013.01); G01R 33/098 (2013.01); G11B 5/3903 (2013.01); H10N 50/85 (2023.02); H10N 50/10 (2023.02); Y10T 428/32 (2015.01)] 8 Claims
OG exemplary drawing
 
1. A photodetection element comprising:
a first ferromagnetic layer configured to be irradiated with light;
a second ferromagnetic layer; and
a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer, wherein
the first ferromagnetic layer includes a first region in contact with the spacer layer and a second region disposed in a position farther from the space layer than the first region,
the first region is made of CoFeB alloy,
an elemental ratio of the CoFeB alloy is Co:Fe:B=15 to 55:25 to 65:15 to 25 under a condition that the sum of Co, Fe, and B corresponds to 100,
the second region is a magnetic material containing Fe and Gd as major constituent elements,
the second region is made of a plurality of sub-layers, and
at least one of the sub-layers includes Fe and one of the sub-layers free of Fe includes Gd wherein when the magnetization state of the second region changes, the magnetization state of the first region that magnetically couples with the second region also changes.