Speaker: Ms. Sukanya Bagchi
Research Supervisor: Dr. Abhishake Mondal
Topic: Giant Magnetoresistance: Basic Concepts and Applications
Date & Time: Thursday, 18th August 2022 at 4:00 PM
Venue: SSCU Auditorium
The tendency of a material (often ferromagnetic) to change the value of its electrical resistance in an externally applied magnetic field is termed as magnetoresistance.1 Giant magnetoresistance (GMR) is a quantum mechanical magnetoresistance effect observed in thin film structures composed of alternating ferromagnetic and nonmagnetic conducting layers.2, 3, 4 In the presence of a magnetic field, the effect manifests as a significant decrease (typically 10 – 80%) in electrical resistance.4 It has opened the way to efficiently control the motion of the electrons by acting on their spin through the orientation of magnetization.4 The GMR was the first step on the path of utilizing the influence of the spin on the mobility of the electrons in ferromagnetic materials to control an electrical current. In 2007, the Nobel Prize in physics was awarded to Prof. Albert Fert and Prof. Peter Grünberg for the discovery of GMR.4 Its application to the read heads of hard disks has contributed significantly to the fast rise in the density of stored information and has led to the extension of hard disk technology to consumer electronics.5 GMR has brought a revolution in the field of magnetic sensors by enhancing the data storage density, thereby leading to the miniaturization of the product and lowering the power consumption. The effect is exploited commercially by manufacturers of hard disk drives and magnetic sensors.
In this seminar, I will discuss the basics of GMR2, 3, different types4, 6, its applications5, 6 (like the read heads of hard disc drives) and some recent developments7.
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- Baibich, M. N.; Broto, J. M.; Fert, A.; Nguyen Van Dau, F.; Petroff, F.; Etienne, P.; Creuzet, G.; Friederich, A.; Chazelas, J., Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett., 1988,61, 2472-2475.
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- Fert, A, Nobel Lecture: Origin, development, and future of spintronics, Rev. Mod. Phys., 2008, 80, 1517-1530
- Chappert, C.; Fert, A; Nguyen Van Dau, F., The emergence of spin electronics in data storage, Nat. Mater., 2007, 6, 813-823.
- Wu, K.; Tonini, D.; Liang, S.; Saha, R.; Chugh, V. K.; Wang, J. P., Giant Magnetoresistance Biosensors in Biomedical Applications. ACS Appl. Mater. Interfaces, 2022,14, 9945-9969.
- Anh, L. D.; Hayakawa, T.; Nakagawa, Y.; Shinya, H.; Fukushima, T.; Kobayashi, M.; Katayama-Yoshida, H.; Iwasa, Y.; Tanaka, M., Ferromagnetism and giant magnetoresistance in zinc-blende FeAs monolayers embedded in semiconductor structures. Nat. Commun., 2021, 12, 4201.