Room-temperature ferromagnetism in ZnO-encapsulated 1.9 nm FePt3 nanoparticle-composite thin films with giant interfacial anisotropy

Abstract

As synthesized 1.9-nm FePt3 nanoparticles are superparamagnetic at room temperature. Coating those nanoparticles with ZnO renders them permanently ferromagnetic with coercivity field of 650 Oe at room temperature. First-principles calculations indicate that giant interfacial anisotropy, induced by the strong spin-orbit interaction of enhanced orbit momentum of Fe, overcomes the superparamagnetic limit, leading to exceptional room-temperature permanent ferromagnetism. The findings are important for the understanding of the origin of permanent ferromagnetism at ultrasmall size and critical for ultrahigh density recording and information processing. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.