Simultaneous magnetic field and field gradient mapping of hexagonal MnNiGa by quantitative magnetic force microscopy

Abstract

Magnetic force microscopy (MFM) is a scanning microscopy technique that is commonly employed to probe the sample’s magnetostatic stray fields via their interaction with a magnetic probe tip. In this work, a quantitative, single-pass MFM technique is presented that maps one magnetic stray-field component and its spatial derivative at the same time. This technique uses a special cantilever design and a special high-aspect-ratio magnetic interaction tip that approximates a monopole-like moment. Experimental details, such as the control scheme, the sensor design, which enables simultaneous force and force gradient measurements, as well as the potential and limits of the monopole description of the tip moment are thoroughly discussed. To demonstrate the merit of this technique for studying complex magnetic samples it is applied to the examination of polycrystalline MnNiGa bulk samples. In these experiments, the focus lies on mapping and analyzing the stray-field distribution of individual bubble-like magnetization patterns in a centrosymmetric [001] MnNiGa phase. The experimental data is compared to calculated and simulated stray-field distributions of 3D magnetization textures, and, furthermore, bubble dimensions including diameters are evaluated. The results indicate that the magnetic bubbles have a significant spatial extent in depth and a buried bubble top base.

A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies

“…For all these reasons, cryptochromes may lead the next generation of the integration of 2D qubits in quantum technology resonators. Recently, MFM measurements were coupled to field gradient mapping by controlling multiple vibration modes [ 372 ], and a microwave probe station was integrated with an MFM setup to furnish simultaneous electrical and microwave contact with an operational spintronic resonator [ 373 ]. These advances will make a fine contribution to mapping local magnetic fields of these nano-oscillators.…”

Mapping the phase-separated state in a 2D magnet

“…This leads to thermally limited force sensitivity at resonance of F min ≃ 4.8 aN Hz −1/2 . Transforming this value into a field sensitivity by applying the magnetic monopole model 60,62,71 for the tip-sample interaction with a value for the magnetic surface charge of q 0 ≃ 3.0 × 10 −9 Am yields a thermally limited field sensitivity of B min ≃ 1.6 nT Hz −1/2 .…”

2024 roadmap on magnetic microscopy techniques and their applications in materials science

“…(p) Manipulation of the micromagnetic state: manipulation of vortices in Nb thin film and observation at 5.5 K. Reprinted from [196] with the permission of AIP Publishing. (q) Magnetic exchange force microscopy: atomic resolution exchange force frequency shift image of a Mn monolayer on W (110) Freitag et al [165] have developed a new cantilever design that uses ultra-soft bending modes and higher flexural modes to simultaneously measure stray fields and their derivatives at the sample surface. This approach can improve surface analysis in materials science, nanotechnology, and biophysics.…”