Abstract
Magnetic sensors to detect magnetic nanoparticles (MNPs) towards biomedical applications require very high sensitivity at low magnetic fields. Here we report a magnetic sensor consisting of a magnetic tunnel junction (MTJ) with a synthetic antiferromagnetic free layer. This sensor exhibits a low magnetic anisotropy and sensitivities of over 18%/Oe at low fields in the range of 0 to 3 Oe. We employ superparamagnetic MNPs with a large diameter of 200 nm. The sensor's transfer curves show the magnetoresistance (MR) variations as a function of MNP concentration. We demonstrate the detection capability of MNP amounts of below 500 ng and low MNP concentrations of 0.01, 0.1, and 1 mg/ml in solvents. This result suggests that the combination of high-sensitivity TMR sensors and large MNPs has a substantial potential for biomarker detection applications.
| Original language | English |
|---|---|
| Article number | 015046 |
| Journal | AIP Advances |
| Volume | 11 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2021 Jan 1 |
Bibliographical note
Funding Information:This research was supported by the S-Innovation program, the Japan Science and Technology Agency (JST, 201106007), the Center for Innovative Integrated Electronic System (CIES), the Center for Spintronics Research Network (CSRN), and the Organization for Advanced Studies, Center for Science and Innovation in Spintronics, the National Research Foundation of Korea (2019R1A2C3006587) and the Korea Evaluation Institute of Industrial Technology (10080408).
Publisher Copyright:
© 2021 Author(s).
ASJC Scopus subject areas
- General Physics and Astronomy