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arXiv · 1709.00281

Quantitative measurements of size-dependent magnetoelectric coupling in Fe3O4 nanoparticles

Kyongjun Yoo·Byung-Gu Jeon·Sae Hwan Chun·Deepak Rajaram Patil·Yong-jun Lim·Seung-hyun Noh·Jihyo Gil·Jinwoo Cheon·Kee Hoon Kim
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Abstract

Bulk magnetite (Fe3O4), the loadstone used in magnetic compasses, has been known to exhibit magnetoelectric (ME) properties below ~10 K; however, corresponding ME effects in Fe3O4 nanoparticles have been enigmatic. We investigate quantitatively the ME coupling of spherical Fe3O4 nanoparticles with uniform diameters (d) from 3 to 15 nm embedded in an insulating host, using a sensitive ME susceptometer. The intrinsic ME susceptibility (MES) of the Fe3O4 nanoparticles is measured, exhibiting a maximum value of ~0.6 ps/m at 5 K for d=15 nm. We found that the MES is reduced with reduced d but remains finite until d=~5 nm, which is close to the critical thickness for observing the Verwey transition. Moreover, with reduced diameter, the critical temperature below which the MES becomes conspicuous increased systematically from 9.8 K in the bulk to 19.7 K in the nanoparticles with d=7 nm, reflecting the core-shell effect on the ME properties. These results point to a new pathway for investigating ME effect in various nanomaterials.

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Kyongjun Yoo, Byung-Gu Jeon, Sae Hwan Chun, Deepak Rajaram Patil, Yong-jun Lim, Seung-hyun Noh, Jihyo Gil, Jinwoo Cheon, Kee Hoon Kim. 2017-09-01. Quantitative measurements of size-dependent magnetoelectric coupling in Fe3O4 nanoparticles. https://doi.org/10.1021/acs.nanolett.6b02978

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