First order reversal curves (FORC) analysis of individual magnetic nanostructures using micro-Hall magnetometry

Alongside the development of artificially createdmagnetic nanostructures, micro-Hall magnetometry has proven to be a versatile tool to obtain high-resolutionhysteresis loop data and access dynamicalproperties. Here we explore the application of First Order Reversal Curves (FORC) —a technique well-established in the field of paleomagnetism for studying grain-size and interaction effects in magnetic rocks—to individual and dipolar-coupled arrays ofmagnetic nanostructures using micro-Hallsensors. A proof-of-principle experiment performed on a macroscopic piece of a floppy disk as a reference sample well known in the literature demonstrates that the FORC diagrams obtained by magnetic stray field measurements using home-builtmagnetometers are in good agreement with magnetization data obtained by a commercial vibrating samplemagnetometer. We discuss in detail the FORC diagrams and their interpretation of three different representative magnetic systems, prepared by the direct-write Focused Electron Beam Induced Deposition (FEBID) technique: (1) an isolated Co-nanoisland showing a simple square-shapedhysteresis loop, (2) a more complex CoFe-alloy nanoisland exhibiting a wasp-waist-typehysteresis, and (3) a cluster of interacting Co-nanoislands. Our findings reveal that the combination of FORC and micro-Hall magnetometry is a promising tool to investigate complex magnetization reversal processes within individual or small ensembles of nanomagnets grown by FEBID or other fabricatio...
Source: Review of Scientific Instruments - Category: Physics Authors: Source Type: research