Ferromagnetic Fe on Cu(001) throughout the fcc-like phase: arguing from the viewpoint of the electronic structure

Abstract

The scientific enthusiasm for ultrathin Fe films on Cu(001) has now lasted for more than 20 years. Is there ferromagnetic iron with a face-centred cubic (fcc) structure? Does ferromagnetism in Fe hinge on the body-centred cubic (bcc) structure? In this contribution, we try to establish that the electron system gives evidence of ferromagnetic behaviour with fcc-like electronic bands. We examine a crystal-induced surface state, which is characteristic of fcc surface order. Furthermore, we compare electronic signatures of fcc and bcc: the d-band exchange splitting, image-potential-state energies and the work function. We conclude that, from the viewpoint of the electronic structure, Fe on Cu(001) is found to be ferromagnetic throughout the fcc-like phase. This result raises a new question: how much deviation from the relaxed fcc order is acceptable without losing the electronic signature of fcc?

Magnetic behavior of metastable Fe films grown on Ir(1 1 1)

“…Among those substrates, Cu is characterized by the smallest lattice mismatch with bulk austenite and therefore has been thoroughly investigated (see, e.g. [8] and references therein). Other attempts are based on Ni, Au, Rh, and also on bcc or hcp substrates, such as W and Ru, respectively [8][9][10][11][12].…”

Electronic structure and magnetism of strained bcc phases across the fcc to bcc transition in ultrathin Fe films

“…Past investigations with averaging techniques such as photoemission spectroscopy (PES) or magneto-optical Kerr effect (MOKE), for instance, detected a not-nil magnetic signal on thin Fe films and related it to the appearance of either low-or high-spin ferromagnetic γ (i.e., fcc) phases [18,19]. However, accurate structural studies performed by scanning tunneling microscopy revealed, also in those cases, the formation of bcc nuclei, calling for a more complex interpretation of the previous experimental results (see, for instance, the ongoing discussion on the growth of Fe on Cu(001) [20,21] or Cu(111) [3]). Our goal is, therefore, to improve, by means of electron spectroscopies, and also with spin resolution, the present understanding of the electronic and magnetic structure of thin Fe films, starting from a more accurate investigation of the spectroscopic signal which is expected from the fcc phase and from the bcc nuclei, and from an assessment of the overall sensitivity of averaging techniques such as PES to the onset of the phase transformation.…”

Structure and Magnetic Properties of Aerosol Nanoparticles of Fe and Its Alloys

“…In a recent paper [130] the results of numerous studies on the epitaxial growth of iron films on the surface of Cu(001) at room temperature have been summarized, and the following generalizations have been supposed. Up to four monolayers the Fe film is FM overall with the easy axis perpendicular to its plane (the 1st level).…”

“…The issue of the possible presence of FM fcc Fe in the FeCu system has been raised repeatedly in the literature [8,109,[129][130][131][132]. It was tried to obtain by heat treatment of ball-milled (BM) both pure iron and iron in a mixture with copper.…”