Effect of Buffer Layers on the Properties of NiFe/Cu/NiFe Trilayers

Bai, Ruru; Qian, Zhenghong; Zhu, Hao; Li, Qiliang; Li, Yuan; Peng, Yuxin; Huo, Dexuan

doi:10.1109/tmag.2016.2614254

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…The magnetic tunnel junction (MTJ) sensor has been shown to have the ability to sense magnetic fields at levels as low as tens of pT and have been broadly applied in many important areas such as geomagnetic detection, magnetic anomaly detection, and navigation [1][2][3][4][5][6][7][8][9]. Usually, an MTJ sensor is combined with a voltage amplifier (VA), feedback circuit, and analog-to-digital converters (ADCs) to form a closed-loop magnetometer as a way to increase the measurement range of the MTJ sensor and improve the linearity of the system [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Equivalent Noise Analysis and Modeling for a Magnetic Tunnel Junction Magnetometer with In Situ Magnetic Feedback

Dou,

Bai,

Sun

et al. 2023

Magnetochemistry

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Magnetic tunnel junction (MTJ) sensors have been one of the excellent candidates for magnetic field detection due to their high sensitivity and compact size. In this paper, we design a magnetometer with in situ magnetic feedback consisting of an MTJ sensor. To analyze and evaluate the detectivity of the MTJ magnetometer, a noise model of the MTJ sensor in the magnetometer without magnetic feedback is first developed. Then, the noise model of the MTJ magnetometer with in situ magnetic feedback is also established, including the noises of the MTJ sensor and the signal conditioning circuit, as well as the feedback circuit. The equivalent noise model of the MTJ magnetometer with in situ magnetic feedback is evaluated through nonlinear fitting for the noise voltage spectrum. Although the noise generated by the MTJ sensor is much greater than that of the signal conditioning circuit, the noise introduced by the feedback coils into the MTJ sensor is slightly more than twice that generated by the MTJ sensor itself. The measurement results show that the detectivity of the MTJ magnetometer with in situ magnetic feedback reaches 526 pT/Hz1/2 at 10 Hz. The equivalent noise analysis method presented in this paper is suitable for the detectivity analysis of magnetometers with magnetic feedback.

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Section: Introductionmentioning

confidence: 99%

Equivalent Noise Analysis and Modeling for a Magnetic Tunnel Junction Magnetometer with In Situ Magnetic Feedback

Dou,

Bai,

Sun

et al. 2023

Magnetochemistry

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“…Compared with AMR sensors, GMR sensors and MTJ sensors have a high sensitivity and small size and have been broadly applied in speed and position sensing in automotive products, weak current detection and magnetic anomaly detection. The detectivity of GMR and MTJ sensors is inferior to that of fluxgates, optically pumped magnetometers and superconducting quantum interference devices mainly due to their higher noise, especially 1/ f noise (Zhang and Xiao, 2019; Yan et al , 2022; Monteblanco et al , 2021; Davies et al , 2021; Bai et al , 2017; Freitas et al , 2007; Qian et al , 2004, 2011; Egelhoff et al , 2009).…”

Section: Introductionmentioning

confidence: 99%

Noise measurement and system calibration on magnetoresistive sensors

Dou

Bai

Zhu

et al. 2023

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Purpose The noise measurement on magnetoresistive (MR) sensors is generally conducted by techniques including single-channel data sampling and fast Fourier transform (FFT) analysis as well as two-channel cross-correlation. The single-channel method is easy to implement and is widely used in the noise measurement on MR sensors, whereas the two-channel method can only eliminate part of the system noise. This study aims to address two key issues affecting measurement accuracy: calibration of the measurement system and the elimination of system noise. Design/methodology/approach The system is calibrated by using a low-noise metal film resistor in that the system noise is eliminated through power spectrum subtraction. Noise measurement and analysis are conducted for both thermal noise and detectivity of magnetic tunnel junction (MTJ) sensor. Findings The thermal noise measurement error is less than 2%. The detectivity of the MTJ sensor reaches 27 pT/Hz1/2 at 2 kHz. Originality/value This study provides a more practical solution for noise measurement and system calibration on MR sensors with a bias voltage and magnetic field.

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“…[25] The PMA constant K CoCrPt of CoCrPt is 3.00 × 10 5 J/m 3 . Meanwhile the process of preparing NiFe thin film by magnetron sputtering is very mature, [26,27] and experiments and theories have shown that the vortex structure can be realized in NiFe thin film. [28][29][30] Therefore, if there is a vortex structure in the NiFe layer, the vortex structure is imprinted into the CoCrPt layer, and then the artificial skyrmion can be realized in CoCrPt.…”

Section: Introductionmentioning

confidence: 99%

Realization of artificial skyrmion in CoCrPt/NiFe bilayers

et al. 2018

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Skyrmion, as a quasi-particle structure, has attracted much attention due to its potential applications in future spintronic devices. Artificial skyrmion structure has aroused great interest as it can be stabilized at room temperature, without needing to incorporate materials with Dzyaloshinskii-Moriya interaction (DMI) into it. In this paper, it is found that the artificial skyrmion structure can be realized in CoCrPt/NiFe bilayers by micromagnetic simulations. The critical magnetic field of the core decreases as the diameter of the NiFe soft magnetic layer increases. The artificial skyrmion has excellent topological protection, and the critical magnetic field of plane is about 76 mT (760 Oe, 1 Oe = 79.5775 A•m −1 ). The external magnetic field plays a key role in determining the core diameter of the skyrmion, and the artificial skyrmion can be realized in CoCrPt/Cu/CoCrPt/NiFe four-layer with a diameter of 13 nm.

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Effect of Buffer Layers on the Properties of NiFe/Cu/NiFe Trilayers

Cited by 3 publications

References 13 publications

Equivalent Noise Analysis and Modeling for a Magnetic Tunnel Junction Magnetometer with In Situ Magnetic Feedback

Equivalent Noise Analysis and Modeling for a Magnetic Tunnel Junction Magnetometer with In Situ Magnetic Feedback

Noise measurement and system calibration on magnetoresistive sensors

Realization of artificial skyrmion in CoCrPt/NiFe bilayers

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