Dr. Leszek Malkinsky

(presenting on September 3, 2025)

Induced Helical Anisotropy in Thin Permalloy Films and Patterns

Abstract

Magnetic properties of materials with magnetic anisotropy depend on the direction of the applied field. Magnetic anisotropy is crucial to application of magnetic materials. It allows engineering magnetic properties for desired applications. For example, hard magnets require high values of anisotropy constants, while magnetic sensors or magnetic shielding prefer small values or no anisotropy. There are different kinds of anisotropy, shape anisotropy, magneto-crystalline anisotropy, growth anisotropy and induced anisotropy. We induced anisotropy in thin films and their patterns using unconventional procedures. During deposition of the Fe-Ni film, in the presence of magnetic field, the substrate was rotated step by step to achieve helical induced anisotropy. Films and patterns show unusual magnetization characteristics: reduced coercivity and linear characteristics, which can be useful for sensor applications. This is due to formation of vortex domains in disc patterns of the films with radius of 20 μm or smaller. Amorphous FeCoB alloys with helical anisotropy show similar properties to those of FeNi alloys.

Speaker Bio

Prof. Malkinski received his PhD degree in 1991 from the Institute of Physics of the Polish Academy of Sciences. Since 1985 He has been doing research on magnetic amorphous and nanocrystalline materials, giant magnetoresistance effect, ferromagnetic resonance, multiferroic composites, ferroelectric solar cells and random access memories. After a postdoctoral position in the Institute of Physics in Warsaw, Poland and the University of Colorado at Colorado Springs he accepted a faculty position at the University of New Orleans where he currently holds the position of a Professor of Physics and Materials Science. He has published over 100 articles on fabrication and characterization of magnetic materials.