title: Effect of substrate interface on the magnetism of supported iron nanoparticles.
abstract: In situ X-ray photo-emission electron microscopy is used to investigate the magnetic properties of iron nanoparticles deposited on different single crystalline substrates, including Si(001), Cu(001), W(110), and NiO(001). We find that, in our room temperature experiments, Fe nanoparticles deposited on Si(001) and Cu(001) show both superparamagnetic and magnetically stable (blocked) ferromagnetic states, while Fe nanoparticles deposited on W(110) and NiO(001) show only superparamagnetic behaviour. The dependence of the magnetic behaviour of the Fe nanoparticles on the contact surface is ascribed to the different interfacial bonding energies, higher for W and NiO, and to a possible relaxation of point defects within the core of the nanoparticles on these substrates, that have been suggested to stabilise the ferromagnetic state at room temperature when deposited on more inert surfaces such as Si and Cu.
authors.affiliation: Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Balan
authors.affiliation: Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, E-08028 Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Fraile Rodríguez
authors.affiliation: Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
authors.forename: C A F
authors.initials: CA
authors.lastname: Vaz
authors.affiliation: Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Kleibert
authors.affiliation: Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Nolting
keywords: Magnetic anisotropy; Magnetic nanoparticles; Photoemission electron microscopy; Superparamagnetism; X-ray magnetic circular dichroism