Bimodal Magnetic Force Microscopy with Capacitive Tip-Sample Distance Control

TL;DR

This paper introduces a bimodal magnetic force microscopy technique that uses a double PLL system to simultaneously measure magnetic interactions and sample topography with controlled tip-sample distance.

Contribution

It presents a novel bimodal MFM method with capacitive distance control using a double PLL system for improved imaging of samples with arbitrary topography.

Findings

Simultaneous acquisition of magnetic and topographical data.

Effective tip-sample distance control via oscillation amplitude.

Enhanced imaging capability for complex sample surfaces.

Abstract

A single-passage, bimodal magnetic force microscopy technique optimized for scanning samples with arbitrary topography is discussed. A double phase-locked loop (PLL) system is used to mechanically excite a high quality factor cantilever under vacuum conditions on its first mode and via an oscillatory tip-sample potential on its second mode. The obtained second mode oscillation amplitude is then used as a proxy for the tip-sample distance, and for the control thereof. With appropriate $z$-feedback parameters two data sets reflecting the magnetic tip-sample interaction and the sample topography are simultaneously obtained.