Investigation of magnetic sensor properties of magnetic tunnel junctions with superparamagnetic free layer at low frequencies for biomedical imaging applications

被引：8

作者：

Ishikawa, Kyohei ^{[1
]}

Oogane, Mikihiko ^{[1
]}

Fujiwara, Kousuke ^{[1
]}

Jono, Junichi ^{[2
]}

Tsuchida, Masaaki ^{[2
]}

Ando, Yasuo ^{[1
]}

机构：

[1] Tohoku Univ, Dept Appl Phys, Sendai, Miyagi 9808579, Japan

[2] Konica Minolta Inc, Machida, Tokyo 1928505, Japan

来源：

JAPANESE JOURNAL OF APPLIED PHYSICS | 2016年 / 55卷 / 12期

基金：

日本科学技术振兴机构;

关键词：

ROOM-TEMPERATURE; MAGNETORESISTANCE;

D O I：

10.7567/JJAP.55.123001

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

The magnetic sensor properties of magnetic tunnel junctions (MTJs) with a superparamagnetic (SP) free layer were systematically investigated at low frequencies (<10 Hz). We prepared four varieties of MTJs with various SP properties by changing the annealing temperature. The temperature dependence of magnetoresistance curves and the signal/noise property at 285K were evaluated. We found that the SP free layer has the advantage of detecting very small and low-frequency AC magnetic fields compared with a ferromagnetic free layer. The SP free layer strongly suppressed magnetic 1/f noise at low frequencies and expressed a very linear response to a small magnetic field. The obtained properties in MTJs with the SP free layer are suitable for detecting biomagnetic fields. The detectivity was 111 nT at low frequencies (from 0.1 to 10Hz), which is one of the highest values in single-MTJ sensors. (C) 2016 The Japan Society of Applied Physics

引用

页数：5

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