Investigating Spin Coupling Across a Three-Dimensional Interface in Core/Shell Magnetic Nanoparticles

Published

March 24, 2020

Author(s)

C. Kons, Manh-Huong Phan, Hariharan Srikanth, D. A. Arena, Zohreh Nemati, Julie Borchers, Kathryn L. Krycka

Abstract

We have used a combination of x-ray magnetic circular dichroism (XMCD) spectroscopy and polarized small angle neutron scattering (P-SANS) to investigate the distribution of magnetization in heterogenous magnetic nanoparticles (NPs) consisting of a metallic Fecore / Fe-oxide shell (CS NPS) or Fe core / partial void layer / oxide shell (CVS NPs). Fe L_2,3 XMCD spectra were analyzed with a combination of experimental metallic Fe XMCD spectra and calculated L-edge spectra for the Fe cations in the oxide shell. Analyses of the temperature-dependent spectra indicate a weak variation of the relative contribution of the metallic and oxide contributions for the CS NPs, and a somewhat larger contribution from the metallic Fe core near the blocking temperature T_B of the CVS NP ensemble. The P-SANS data also indicate a larger variation in the magnetization of the CVS NPs near T_B. Modeling of the spin-dependent neutron scattering reveals large variations in the radial magnetization distribution, with a region of reversed magnetization adjacent to the metallic core. Interfacial roughness may play a role in the development of this magnetization profile.

Citation

Physical Review Materials

Volume

4

Issue

3

Pub Type

Journals

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Keywords

Magnetic Nanoparticles, Small Angle Neutron Scattering, Neutron Polarization, Core/Shell, XMCD

Citation

Kons, C. , Phan, M. , Srikanth, H. , Arena, D. , Nemati, Z. , Borchers, J. and Krycka, K. (2020), Investigating Spin Coupling Across a Three-Dimensional Interface in Core/Shell Magnetic Nanoparticles, Physical Review Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929993 (Accessed December 26, 2024)