Characterization of Magnetic Colloids

Our Magnetic Analysis Platform

Alfa Chemistry's Analysis Center has introduced a large number of advanced magnetic characterization equipment, our technologies include but are not limited to:

• Superconducting quantum interference device magnetometry (SQUID)

SQUID is a tool to measure the magnetic properties of nanomaterials. A scanning magnetic microscope incorporating nanoSQUIDs has also been developed. NanoSQUIDs are probes for nanoscale magnetic imaging and spectroscopy with the advantage of directly measuring magnetization changes in small spin systems.

Fig.1 Scheme of the experimental set up for the nanoparticle magnetization measurements.^[2]

• Vibrating sample magnetometry (VSM)

VSM is another method that can be used to record the M-H rings of magnetic nanomaterials and obtain parameters such as magnetization saturation (M_S) and magnetization remanence (M_R).

• Mössbauer spectroscopy

Mössbauer spectroscopy is an analytical tool based on the recoilless resonance fluorescence of gamma photons in substances with Mössbauer active elements such as Fe. Mössbauer can be used to evaluate the oxidation state, symmetry and spin state and magnetic ordering of Fe atoms in nanoparticle samples, thereby identifying magnetic phases in the sample. Furthermore, for magnetically ordered materials, Mössbauer spectra recorded as a function of temperature can be used to estimate the magnetic anisotropy energy and quantify pyrolytic blocking (superparamagnetism).

Fig.2 Schematic diagram of a transmission Mössbauer spectrometer system.^[3]

• X-ray magnetic circular dichroism (XMCD)

XMCD is a local probe technique used to study the site symmetry and magnetic moment of transition metal ions in ferromagnetic and ferrimagnetic materials. The principle of XMCD is to apply an external magnetic field along the X-ray propagation vector, exploit the differential absorption of the left and right circularly polarized light in the magnetic field, and record the measurement results at the edge of the transition element.

• Ferromagnetic resonance (FMR)

FMR is a spectroscopic technique used to probe the magnetization of ferromagnetic materials including nanoscale materials. It shares certain similarities with EPR and NMR. FMR spectroscopy can provide information about the average shape and size distribution of nanoparticles.

• Superparamagnetic relaxometry (SPMR)

SPMR is a technique that combines sensitive magnetic sensors with the superparamagnetic properties of Fe₃O₄ nanoparticles. It is an emerging technology that can be applied in fields such as cancer research, for example, the functionalization of nanoparticles with biomarkers allows specific binding to cancer cells.

Our Advantages

Alfa Chemistry has accumulated many years of experience in colloidal characterization and you can find the performance characterization of almost all colloidal materials in our list of services. Our characterization services have several advantages:

References

1. Stefanos Mourdikoudis, et al. Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties. Nanoscale. 2018.
2. Carmine Granata. et al. Magnetic properties of iron oxide nanoparticles investigated by nanoSQUIDs.The European Physical Journal B. 2013, 86(6):1-5.
3. Oh S J, et al. Mössbauer analysis on the magnetic properties of Fe–Co nanoparticles synthesized by chemical vapor condensation process. Journal of Magnetism & Magnetic Materials. 2004, 280(2-3):147-157.

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