Y. Zabila

Wearable Magnetic Field Sensors for Flexible Electronics

Highly flexible bismuth Hall sensors on polymeric foils are fabricated, and the key optimization steps that are required to boost their sensitivity to the bulk value are identified. The sensor can be bent around the wrist or positioned on the finger to realize an interactive pointing device for wearable electronics. Furthermore, this technology is of great interest for the rapidly developing market of -eMobility, for optimization of eMotors and magnetic bearings.

Chemical order and crystallographic texture of FePd:Cu thin alloy films

FePd thin films have been recently considered as promising materials for high-density magnetic storage devices. However, it is necessary to find a proper method of fabrication for the (001)-textured and chemically well-ordered alloy. In this paper, we present the detailed investigations of lattice parameters, chemical order degree, grain sizes, and crystallographic texture carried out on FePd alloys with 10 at.% of Cu addition. The initial [Cu(0.2 nm)/Fe(0.9 nm)/Pd(1.1 nm)]5 multilayers were thermally evaporated in an ultrahigh vacuum on MgO(100), Si(100), Si(111), and Si(100) covered by a 100-nm-thick layer of amorphous SiO2. In order to obtain a homogeneous FePd:Cu alloy, the multilayers were annealed in two different ways. First, the samples were rapidly annealed in nitrogen atmosphere at 600 °C for 90 seconds. Next, the long annealing in a high vacuum for 1 h at 700 °C was done. This paper focuses on quantitative investigations of the chemical order degree and crystallographic texture of ternary FePd:...

X-ray absorption fine structure and x-ray diffraction studies of crystallographic grains in nanocrystalline FePd:Cu thin films

FePd alloys have recently attracted considerable attention as candidates for ultrahigh density magnetic storage media. In this paper we investigate FePd thin alloy film with a copper admixture composed of nanometer-sized grains. [Fe(0.9 nm)/Pd(1.1 nm)/Cu(d nm)]×5 multilayers were prepared by thermal deposition at room temperature in UHV conditions on Si(100) substrates covered by 100 nm SiO2. The thickness of the copper layer has been changed from 0 to 0.4 nm. After deposition, the multilayers were rapidly annealed at 600 °C in a nitrogen atmosphere, which resulted in the creation of the FePd:Cu alloy. The structure of alloy films obtained this way was determined by x-ray diffraction (XRD), glancing angle x-ray diffraction, and x-ray absorption fine structure (EXAFS). The measurements clearly showed that the L10 FePd:Cu nanocrystalline phase has been formed during the annealing process for all investigated copper compositions. This paper concentrates on the crystallographic grain features of FePd:Cu alloy...

Influence of Superparamagnetism on Exchange Anisotropy at CoO/[Co/Pd] Interfaces

Magnetic systems exhibiting an exchange bias effect are being considered as materials for applications in data storage devices, sensors, and biomedicine. Because the size of new magnetic devices is being continuously reduced, the influence of thermally induced instabilities in magnetic order has to be taken into account during their fabrication process. In this study, we show the influence of superparamagnetism on the magnetic properties of an exchange-biased [CoO/Co/Pd]10 multilayer. We find that the process of progressive thermal blocking of the superparamagnetic clusters causes an unusually fast rise of the exchange anisotropy field and coercivity and promotes easy-axis switching to the out-of-plane direction.

Exchange Bias in the [CoO/Co/Pd]10 Antidot Large Area Arrays

Magnetic nanostructures revealing exchange bias effect have gained a lot of interest in recent years due to their possible applications in modern devices with various functionalities. In this paper, we present our studies on patterned [CoO/Co/Pd]10 multilayer where ferromagnetic material is in a form of clusters, instead of being a continuous layer. The system was patterned using nanosphere lithography technique which resulted in creation of an assembly of well-ordered antidots or islands over a large substrate area. We found that the overall hysteresis loop of the films consists of hard and soft components. The hard component hysteresis loop exhibits a large exchange bias field up to -11 kOe. The patterning process causes a slight increase of the exchange field as the antidot radius rises. We also found that the material on edges of the structures gives rise to a soft unbiased magnetization component.