Interfacial ferromagnetism and atomic structures in high-temperature grown Fe3O4/Pt/Fe3O4 epitaxial trilayers

Abstract

Induced Pt ferromagnetism in Fe3O4/Pt/Fe3O4 epitaxial trilayer films has been investigated by means of X-ray magnetic circular dichroism (XMCD) at the Pt L3,2-edges at various temperatures from 300K to 12K, including the metal-insulator transition temperature of Fe3O4 (TV∼114K). At all the temperatures, we observed clear XMCD signals due to Pt ferromagnetism, the amplitude of which was determined to be 0.39μB at 300K and 0.52μB at 12K for the sample with the Pt thickness of ∼2nm. Interestingly, these values are comparable to or even greater than those in Pt/3d-ferromagnetic-metal (Fe, Ni, Co, and Ni81Fe19) junction systems. The results can be interpreted in terms of a possible Fe interdiffusion into the Pt layer and also possible Fe-Pt alloying due to its high-temperature deposition.