Magnetic properties of individual Co2FeGa Heusler nanoparticles studied at room temperature by a highly sensitive co-resonant cantilever sensor

Abstract

The investigation of properties of nanoparticles is an important task to pave the way for progress and new applications in many fields of research like biotechnology, medicine and magnetic storage techniques. The study of nanoparticles with ever decreasing size is a challenge for commonly employed methods and techniques. It requires increasingly complex measurement setups, often low temperatures and a size reduction of the respective sensors to achieve the necessary sensitivity and resolution. Here, we present results on how magnetic properties of individual nanoparticles can be measured at room temperature and with a conventional scanning force microscopy setup combined with a co-resonant cantilever magnetometry approach. We investigate individual Co2FeGa Heusler nanoparticles with diameters of the order of 35 nm encapsulated in carbon nanotubes. We observed, for the first time, magnetic switching of these nanoparticles in an external magnetic field by simple laser deflection detection. Furthermore, we were able to deduce magnetic properties of these nanoparticles which are in good agreement with previous results obtained with large nanoparticle ensembles in other experiments. In order to do this, we expand the analytical description of the frequency shift signal in cantilever magnetometry to a more general formulation, taking unaligned sensor oscillation directions with respect to the magnetic field into account.

Superparamagnetic nanoarchitectures for disease-specific biomarker detection

“…microcantilevers,296,297 and resonance Rayleigh scattering (RRS),298 play critical roles in the development of a sandwich assay for proteinbased biomarker detection. Engineered MNPs for disease-specific biomolecular (electrochemical and optical) sensing…”

A Comprehensive Categorization of Micro/Nanomechanical Resonators and Their Practical Applications from an Engineering Perspective: A Review

“…Therefore, such devices can pave the way for evaluating magnetic properties of nanoparticles (such as Co2FeGa Heusler) under simple experimental conditions at the room temperature. [ 428 ]…”

Effective Sensor Properties of a Novel Co-Resonant Cantilever Sensor

“…In order to give some graphical representation of the effective sensor properties, an exemplary sensor with parameters summarized in Table 1 is considered. These numerical values are based on experimental sensor realizations [1,2]. Figure 1b depicts an exemplary amplitude response curve of the coupled system obtained for the microcantilever and based on the parameters from Table 1 and for −2% eigenfrequency deviation, i.e., the nanocantilever's eigenfrequency is 2% lower than that of the microcantilever.…”

“…Co-resonant cantilever sensors have been shown to tremendously increase the signal strength in proof-of-principle experiments in cantilever magnetometry and magnetic force microscopy (MFM) [1][2][3]. Since the measurement principle is only based on the coupling and eigenfrequency matching (termed as co-resonance) of a micro-and a nanocantilever, it could potentially by extended to other applications for dynamic-mode cantilever sensors, for example gas sensing ('artificial nose') [4] or mass sensors [5].…”