biostudies-literatureSpaeth PDutch Research Council (NWO)3645-3650https://www.ebi.ac.uk/biostudies/studies/S-EPMC9101077biostudies-literatureUnknown22(9)Magnetic imaging is a versatile tool in biological and condensed-matter physics. Existing magnetic imaging techniques either require demanding experimental conditions which restrict the range of their applications or lack the spatial resolution required for single-particle measurements. Here, we combine photothermal (PT) microscopy with magnetic circular dichroism (MCD) to develop a versatile magnetic imaging technique using visible light. Unlike most magnetic imaging techniques, photothermal magnetic circular dichroism (PT MCD) microscopy works particularly well for single nanoparticles immersed in liquids. As a proof of principle, we demonstrate magnetic CD imaging of superparamagnetic magnetite nanoparticulate clusters immersed in microscope immersion oil. The sensitivity of our method allowed us to probe the magnetization curve of single ∼400-nm-diameter magnetite nanoparticulate clusters.Nano lettersImaging the Magnetization of Single Magnetite Nanoparticle Clusters via Photothermal Circular Dichroism.PMC9101077OTP 16008NanoFront, Zwaartekrachtpremie 2012Spinoza OrritSpaeth PLahabi KAdhikari SOrrit MWang YBaaske MDfalseImaging the Magnetization of Single Magnetite Nanoparticle Clusters via Photothermal Circular Dichroism.Magnetic imaging is a versatile tool in biological and condensed-matter physics. Existing magnetic imaging techniques either require demanding experimental conditions which restrict the range of their applications or lack the spatial resolution required for single-particle measurements. Here, we combine photothermal (PT) microscopy with magnetic circular dichroism (MCD) to develop a versatile magnetic imaging technique using visible light. Unlike most magnetic imaging techniques, photothermal magnetic circular dichroism (PT MCD) microscopy works particularly well for single nanoparticles immersed in liquids. As a proof of principle, we demonstrate magnetic CD imaging of superparamagnetic magnetite nanoparticulate clusters immersed in microscope immersion oil. The sensitivity of our method allowed us to probe the magnetization curve of single ∼400-nm-diameter magnetite nanoparticulate clusters.2022-01-01T00:00:00Z2022 May2025-04-04T22:53:15.622Z2025-02-19T00:55:53.742ZS-EPMC91010773542083010.1021/acs.nanolett.2c00178