Direct Observation of Magnetic Metastability in Individual Iron Nanoparticles

Elemental and magnetic contrast images in the initial state before the magnetic field is applied
Elemental and magnetic contrast images in the initial state before the magnetic field is applied
Studying the magnetization of individual iron (Fe) nanoparticles by magnetic spectromicroscopy reveals that superparamagnetic (SPM) and ferromagnetic blocked (FM) nanoparticles can coexist in the investigated size range of 8-20 nm. Spontaneous transitions from the blocked state to the superparamagnetic state are observed in single particles and suggest that the enhanced magnetic energy barriers in the ferromagnetic particles are due to metastable, structurally excited states with unexpected life times.

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Contact
Dr. Armin Kleibert, Swiss Light Source
Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
Phone: +41 56 310 5527, e-mail: armin.kleibert@psi.ch

Prof. Dr. Frithjof Nolting, Swiss Light Source
Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
Phone: +41 56 310 5111, e-mail: frithjof.nolting@psi.ch
Original Publication
Direct Observation of Magnetic Metastability in Individual Iron Nanoparticles
Ana Balan, Peter M. Derlet, Arantxa Fraile Rodríguez, Joachim Bansmann, Rocio Yanes, Ulrich Nowak, Armin Kleibert, and Frithjof Nolting, Phys. Rev. Lett. 112, 107201 (2014)
DOI: 10.1103/PhysRevLett.112.107201