• permanent (hard) ferromagnetism;
  • spin-orbit interaction;
  • giant interfacial anisotropy;
  • superparamagnetic;
  • FePt/ZnO
Thumbnail image of graphical 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.