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Bereich: Suchergebnisse
Publikation Tracking the orientation of deep brain stimulation electrodes using an embedded magnetic sensor(2021) Vergne, Céline; Madec, Morgan; Hemm-Ode, Simone; Quirin, Thomas; Vogel, Dorian; Hebrard, Luc; Pascal, JorisThis paper proposes a three-dimensional (3D) orientation tracking method of a 3D magnetic sensor embedded in a 2.5 mm diameter electrode. Our system aims to be used during intraoperative surgery to detect the orientation of directional leads (D-leads) for deep brain stimulation (DBS).06 - PräsentationPublikation Low-coercivity perpendicular spin transfer torque magnetic tunnel junctions as nanoscale magnetic sensors(IEEE, 09/2023) Nicolas, Hugo; Sousa, Ricardo C.; Mora-Hernández, Ariam; Prejbeanu, Ioan-Lucian; Hebrard, Luc; Kammerer, Jean-Baptiste; Pascal, JorisThis paper presents the use of the spin transfer torque effect in perpendicular magnetic tunnel junctions to operate the devices as magnetic sensors. The junctions, specifically designed for sensing applications exhibit close to low-coercivity, allowing the sensitivity to be as high as 25 mV/mT for a large dynamic range of 20 mT. In addition, the junctions have diameters ranging from 20 to 100 nanometers, making them among the smallest magnetic sensing elements ever reported to our knowledge. A single operational amplifier operates the junction and outputs a voltage proportional to the external magnetic field. This paper opens the way to a monolithic integration of both the conditioning electronics and the perpendicular magnetic tunnel junction.04B - Beitrag KonferenzschriftPublikation Conditioning circuits for nanoscale perpendicular spin transfer torque magnetic tunnel junctions as magnetic sensors(IEEE, 2023) Nicolas, Hugo; Sousa, Ricardo C.; Mora-Hernández, Ariam; Prejbeanu, Ioan-Lucian; Hebrard, Luc; Kammerer, Jean-Baptiste; Pascal, JorisThis article demonstrates a new type of magnetic sensor using a perpendicular spin transfer torque magnetic tunnel junction (MTJ). The sensing element has a cylindrical shape of 50 nm in diameter and is to our knowledge among the smallest magnetic sensor ever reported. This article describes the principle of operation of the sensing element and the associated signal processing electronics, which delivers a signal proportional to the external magnetic field. Experimental results are detailed and compared to the state-of-the-art commercially available integrated magnetic sensors as well as published magnetoresistive sensors based on MTJs with comparable size. The measured sensitivity of the developed sensor is 1.28 V/T, and its dynamic range reaches 80 mT. The measured noise level is 21.8μT/√ Hz. Two different operating principles of the proposed sensor are described and compared, one based on a time-to-digital converter and one based on a pulsewidth-modulated (PWM) signal. Both methods require only standard microelectronics components, which are suitable for monolithic integration of the sensing element with its conditioning electronics. Subsequent improvements of the sensing element as well as conditioning electronics are required to further lower the noise level. The sensing element and its conditioning electronics are compatible with fabrication processes already used in magnetic random access memory fabrication. This opens the way to mass production and addresses various markets, such as consumer electronics, automotive, industrial sensing, physics experiments, or medical devices.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Assessment of the impact of static field inhomogeneity on the performance of miniaturized NMR devices(IEEE, 2023) Baumgarten, Guilherme; Madec, Morgan; Nguyen, Duc-Vinh; Werling, Lucas; Pascal, Joris; Gajendramurthy, Chunchesh Malangi; Bertani, Philippe; Djukic, Jean-Pierre; Hebrard, Luc01A - Beitrag in wissenschaftlicher ZeitschriftPublikation A magnetic sensor based on a nanometric spin transfer torque magnetic tunnel junction suitable for monolithic integration(IEEE, 2022) Nicolas, Hugo; Pascal, Joris; Hebrard, Luc; Kammerer, Jean-Baptiste; Sousa, Ricardo C.; Mora-Hernandez, Ariam; Prejbeanu, Ioan-Lucian04B - Beitrag KonferenzschriftPublikation Towards tracking of deep brain stimulation electrodes using an integrated magnetometer(MDPI, 10.04.2021) Quirin, Thomas; Féry, Corentin; Vogel, Dorian; Vergne, Céline; Sarracanie, Mathieu; Salameh, Najat; Madec, Morgan; Hemm-Ode, Simone; Hebrard, Luc; Pascal, JorisThis paper presents a tracking system using magnetometers, possibly integrable in a deep brain stimulation (DBS) electrode. DBS is a treatment for movement disorders where the position of the implant is of prime importance. Positioning challenges during the surgery could be addressed thanks to a magnetic tracking. The system proposed in this paper, complementary to existing procedures, has been designed to bridge preoperative clinical imaging with DBS surgery, allowing the surgeon to increase his/her control on the implantation trajectory. Here the magnetic source required for tracking consists of three coils, and is experimentally mapped. This mapping has been performed with an in-house three-dimensional magnetic camera. The system demonstrates how magnetometers integrated directly at the tip of a DBS electrode, might improve treatment by monitoring the position during and after the surgery. The three-dimensional operation without line of sight has been demonstrated using a reference obtained with magnetic resonance imaging (MRI) of a simplified brain model. We observed experimentally a mean absolute error of 1.35 mm and an Euclidean error of 3.07 mm. Several areas of improvement to target errors below 1 mm are also discussed.01A - Beitrag in wissenschaftlicher Zeitschrift