A new 3D-nanoprinted anomalous Scanning Hall Probe for quantitative micromagnetic measurements

Abstract

Atomic Force Microscopy (AFM) is a widely used surface analysis technique at the nanoscale relying on a sharp Silicon tip touching the sample surface and tracking its movement while rastering over the surface. In order to investigate magnetic properties this tip can be functionalized with magnetic material as realized in Magnetic Force Microscopy (MFM) or a Hall sensor can be implemented on the AFM cantilever which is the basis for Scanning Hall Probe Microscopy (SHPM). A Hall sensor allows to measure a sample stray field through a Hall voltage building up in the sensor area in proportion to the applied field. If the Hall sensor consists of magnetic material, its field response depends on the sensor magnetization, an effect which is called anomalous Hall effect. While in MFM images high lateral resolutions and good magnetic contrast can be reached, SHPM yields the possibility to quantitatively determine the magnetic properties of a sample. In this work, we explore a new 3D-nanoprinting technique called Focused Electron Beam Induced Deposition (FEBID) for the fabrication of MFM tips and SHPM sensors and investigate the fabricated probes and their performance in order to further develop these magnetic measurement modes. We show that the magnetic and lateral resolution of FEBID structured MFM tips is comparable or better than for commercial MFM tips. In addition we show the first SHPM images obtained with an anomalous Hall sensor in air and vacuum. With this, we show the potential of FEBID for the fabrication of MFM tips and make a first step towards quantitative magnetic measurements obtained with FEBID structured SHPM cantilevers based on the anomalous Hall effect. Combining the results from micromagnetic simulations with the possibilities given by FEBID structuring we want to pave a path towards better lateral and magnetic resolution in SHPM.