Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: T023
DOI: https://doi.org/10.24326/ICDSUPL2.T023
Published online: 19 April 2023
ICDSUPL, 2, T023 (2023)
Giant magnetoresistance – technology of thin-film structures and their potential applications
Jakub Kisała1*
1 Department of Electronics and Information Technology; Faculty of Electrical Engineering and Computer Science; Lublin University of Technology, Nadbystrzycka 38 A, 20-618 Lublin, Poland
* Corresponding author: j.kisala@pollub.pl
Abstract
Nowadays, almost all everyday devices are probably equipped with various types of sensors. Their ubiquity motivates the constant search for newer solutions as well as improvements to existing ones. One phenomenon that can serve as a starting point for the development of a wide range of sensors is the giant magnetoresistance effect. This phenomenon involves a change in the electrical resistance of a suitably structured sample under the influence of an external magnetic field. The structures in which the GMR phenomenon is observed are thin-film structures consisting of ferromagnetic layers punctuated by layers with weak magnetic properties. At the Lublin University of Technology, such structures exhibiting the phenomenon of giant magnetoresistance are produced. For this purpose, the magnetron sputtering method is used. Using materials such as nickel, permaloy, aluminum, platinum and copper, structures are produced for which several-ohm changes in electrical resistance are observed. Measurements of DC resistance are carried out with a multimeter along with the use of a constructed work station whose source of the external magnetic field is two strong neodymium magnets. Changing the distance between the magnet’s covers results in a change in value of the magnetic field intensity affecting the structure. The value of the obtained resistive changes of the sample is determined by many factors, mainly; the materials of the layers, the parameters of the technological process (e.g. vacuum pressure in the chamber), the thickness of individual layers, the dimensions of the structure. Additional technological processes, i.e. magnetic annealing and application of an external magnetic field during the sputtering process, are also used in the sequence of manufacturing thin structures. These processes are aimed at easier manipulation of the magnetization direction of individual ferromagnetic layers of the final structure. The application of such structures as magnetic field sensors comes to mind as obvious. Such sensors are an interesting alternative to the widespread sensors based on the Hall phenomenon. They find applications in NDT non-destructive diagnostic systems, as well as, due to the possibility of obtaining small-sized structures, they are used in medicine in the form of scanning probes and arrays aimed at detecting proteins and bacteria, among others. GMR sensors are also widely used in automotive applications.
How to cite
J. Kisała, 2023. Giant magnetoresistance – technology of thin-film structures and their potential applications. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.T023