Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers
The automotive industry requires magnetic sensors exhibiting highly linear output within a dynamic range as wide as ±1 kOe. A simple model predicts that the magneto-conductance (G-H) curve in a magnetic tunnel junction (MTJ) is perfectly linear, whereas the magneto-resistance (R-H) curve inevitably...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIP Publishing LLC
2018-04-01
|
| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/1.5027768 |
| _version_ | 1831792983823876096 |
|---|---|
| author | T. Nakano M. Oogane T. Furuichi Y. Ando |
| author_facet | T. Nakano M. Oogane T. Furuichi Y. Ando |
| author_sort | T. Nakano |
| collection | DOAJ |
| description | The automotive industry requires magnetic sensors exhibiting highly linear output within a dynamic range as wide as ±1 kOe. A simple model predicts that the magneto-conductance (G-H) curve in a magnetic tunnel junction (MTJ) is perfectly linear, whereas the magneto-resistance (R-H) curve inevitably contains a finite nonlinearity. We prepared two kinds of MTJs using in-plane or perpendicularly magnetized synthetic antiferromagnetic (i-SAF or p-SAF) reference layers and investigated their sensor performance. In the MTJ with the i-SAF reference layer, the G-H curve did not necessarily show smaller nonlinearities than those of the R-H curve with different dynamic ranges. This is because the magnetizations of the i-SAF reference layer start to rotate at a magnetic field even smaller than the switching field (Hsw) measured by a magnetometer, which significantly affects the tunnel magnetoresistance (TMR) effect. In the MTJ with the p-SAF reference layer, the G-H curve showed much smaller nonlinearities than those of the R-H curve, thanks to a large Hsw value of the p-SAF reference layer. We achieved a nonlinearity of 0.08% FS (full scale) in the G-H curve with a dynamic range of ±1 kOe, satisfying our target for automotive applications. This demonstrated that a reference layer exhibiting a large Hsw value is indispensable in order to achieve a highly linear G-H curve. |
| first_indexed | 2024-12-22T15:22:46Z |
| format | Article |
| id | doaj.art-b8e98f7a836f49a1b8137951c6dfbca2 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-22T15:22:46Z |
| publishDate | 2018-04-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-b8e98f7a836f49a1b8137951c6dfbca22022-12-21T18:21:35ZengAIP Publishing LLCAIP Advances2158-32262018-04-0184045011045011-610.1063/1.5027768039804ADVMagnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layersT. Nakano0M. Oogane1T. Furuichi2Y. Ando3Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-05, Sendai 980-8579, JapanDepartment of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-05, Sendai 980-8579, JapanDENSO Corporation, Showa-machi 1-1, Kariya, Aichi 448-4661, JapanDepartment of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-05, Sendai 980-8579, JapanThe automotive industry requires magnetic sensors exhibiting highly linear output within a dynamic range as wide as ±1 kOe. A simple model predicts that the magneto-conductance (G-H) curve in a magnetic tunnel junction (MTJ) is perfectly linear, whereas the magneto-resistance (R-H) curve inevitably contains a finite nonlinearity. We prepared two kinds of MTJs using in-plane or perpendicularly magnetized synthetic antiferromagnetic (i-SAF or p-SAF) reference layers and investigated their sensor performance. In the MTJ with the i-SAF reference layer, the G-H curve did not necessarily show smaller nonlinearities than those of the R-H curve with different dynamic ranges. This is because the magnetizations of the i-SAF reference layer start to rotate at a magnetic field even smaller than the switching field (Hsw) measured by a magnetometer, which significantly affects the tunnel magnetoresistance (TMR) effect. In the MTJ with the p-SAF reference layer, the G-H curve showed much smaller nonlinearities than those of the R-H curve, thanks to a large Hsw value of the p-SAF reference layer. We achieved a nonlinearity of 0.08% FS (full scale) in the G-H curve with a dynamic range of ±1 kOe, satisfying our target for automotive applications. This demonstrated that a reference layer exhibiting a large Hsw value is indispensable in order to achieve a highly linear G-H curve.http://dx.doi.org/10.1063/1.5027768 |
| spellingShingle | T. Nakano M. Oogane T. Furuichi Y. Ando Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers AIP Advances |
| title | Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| title_full | Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| title_fullStr | Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| title_full_unstemmed | Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| title_short | Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| title_sort | magnetic sensor performance evaluated from magneto conductance curve in magnetic tunnel junctions using in plane or perpendicularly magnetized synthetic antiferromagnetic reference layers |
| url | http://dx.doi.org/10.1063/1.5027768 |
| work_keys_str_mv | AT tnakano magneticsensorperformanceevaluatedfrommagnetoconductancecurveinmagnetictunneljunctionsusinginplaneorperpendicularlymagnetizedsyntheticantiferromagneticreferencelayers AT moogane magneticsensorperformanceevaluatedfrommagnetoconductancecurveinmagnetictunneljunctionsusinginplaneorperpendicularlymagnetizedsyntheticantiferromagneticreferencelayers AT tfuruichi magneticsensorperformanceevaluatedfrommagnetoconductancecurveinmagnetictunneljunctionsusinginplaneorperpendicularlymagnetizedsyntheticantiferromagneticreferencelayers AT yando magneticsensorperformanceevaluatedfrommagnetoconductancecurveinmagnetictunneljunctionsusinginplaneorperpendicularlymagnetizedsyntheticantiferromagneticreferencelayers |