Magnetic Dead Layers Induced by Strain at fct Fe/Rh(001) Interface

Abstract

We have studied magnetic properties of face-centered-tetragonal (fct) Fe thin films grown at room temperature on the Rhð001Þ surface. Band structure calculations show that the stable magnetic phase of fct Fe on the Rhð001Þ surface is ferromagnetic (FM), which agrees with our previous conclusion obtained by angle-resolved photoelectron spectroscopy and spin-and angle-resolved photoelectron spectroscopy (SARPES) of the four monolayers (ML) Fe film [K. Hayashi et al.: Phys. Rev. B 64 (2001) 054417]. This magnetic phase of fct Fe is also confirmed by the SARPES spectra of 3 ML Fe/Rhð001Þ. On the other hand the thickness dependence of the Curie temperature estimated by SARPES and of local magnetic moment by soft X-ray magnetic circular dichroism experiments show that the Fe films below 2 ML are not FM, i.e., they are magnetic dead layers. We conclude that these magnetic dead layers are caused by a large strain at the Fe/Rhð001Þ interface.KEYWORDS: face-centered-tetragonal Fe thin film, lattice strain, magnetic dead layer, spin-and angle-resolved photoelectron spectroscopy, soft X-ray magnetic circular dichroism

Magnetism of 3dtransition-metal monolayers on Rh(100)

“…For example, no notable intermixing has been encountered at the interface of Fe/Rh(100) during growth of Fe films. 20 Epitaxial, pseudomorphic layer-by-layer growth of one and two layers of Co on Rh(100) was reported by Begley et al, 21 and several groups 20,[22][23][24] have been able to grow pseudomorphically even thicker films of face-centered tetragonal Fe on Rh(100). Recent reports show that FeCo alloys can be grown on Rh(100) where the composition of the alloy can be used to tailor the magnetic anisotropy of the system.…”

“…With the exception of Ni, in all cases the equilibrium distance between the interface Rh layer and the bulk Rh underneath, d 23 , increases with respect to the substrates' bulk interlayer spacing. Moving from left to right through the periodic table, we find that d 23 decreases, supporting the interpretation that the d-band filling controls these relaxations.…”

“…The relaxations of the interlayer spacing between the 3d monolayer and the topmost substrate layer, d 12 , and the first Rh interlayer spacing, d 23 , are presented in Fig. 1 for both FM and AFM configurations.…”

“…25 Moreover, the same group used Rh(100) spacers to achieve a FM or AFM interlayer exchange coupling depending on the Rh thickness. 26 Hayashi et al 23,24 concluded on the basis of soft x-ray magnetic circular dichroism experiments measured at room temperature that a monolayer and a bilayer of Fe are not ferromagnetic and interpreted them as magnetically dead, caused by the large strain exerted in the interface of the thin film and the substrate. Hwang et al 27 found experimentally a suppression of the ferromagnetic order of Fe overlayers on the Rh(100) surface, and they as well as Spisak and Hafner 28 predicted a c(2 × 2) AFM order for one ML Fe on Rh(100) on the basis of DFT calculations.…”

Antiferromagnetic Ordering in the Fe(001) Monolayer Mediated by the Ir Substrate

“…There exist reliable low energy electron diffraction (LEED) measurements (elucidating the detailed geometry) on very thin overlayers grown on Ir substrate with negligible Fe-Ir intermixing [9]. Furthermore, magneto-optical Kerr effect studies found no magnetization of iron overlayers thinner than ≈ 4 monolayers on Ir(001) [9] and ≈ 2 monolayers on Rh(001) [11]. The Fe/Ir system is a good candidate to investigate the magnetic properties of ultrathin films, since both materials grow in a two-dimensional atomic layer- * This paper was presented at 10th International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN-10), Granada Conference Centre, Spain, 21-25 September, 2009.…”