Magnetic Properties of Fe@Pt Nanoparticles with Core/Shell Morphology

A. ZeleňákováaV. Zeleňákb, J. Bednarčíkc, M. Laudaa and J. Kováčd aDepartment of Solid State Physics, P.J. Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia bDepartment of Inorganic Chemistry, P.J. Šafárik University, Moyzesova 11, 04001 Košice, Slovakia cDESY-Hasylab, Notkestr. 85, Hamburg, Germany dInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia

Full Text PDF

We have investigated the magnetic properties of iron nanoparticles coated by platinum shell prepared by chemical procedure. Magnetic measurements using SQUID magnetometer confirm the behaviour typical for a superparamagnetic system. From the M(H) loop at 300 K the magnetic moment of each particle mP ≈ 250 μB was calculated. The magnetic relaxation study by the in-phase χ' and out-of-phase χ" ac susceptibilities in frequency range 0.1-1000 Hz suggests the existence of two magnetic layers with different magnetic spin's dynamics and strong dipolar interactions between nanoparticles. The observed magnetic behaviour is caused by the blocking process of interacting superparamagnetic particles with magnetic iron core, diamagnetic platinum shell and spin-glass like behaviour magnetic interlayer between them.

DOI: 10.12693/APhysPolA.118.1002 PACS numbers: 75.75.Fk, 75.50.Vv, 75.40.Gb