Spin Polarization of Metal (Mn, Fe, Cu, and Mg) and Metal-Free Phthalocyanines on an Fe(100) Substrate

Abstract

The electronic structure and spin asymmetry of metal phthalocyanines (Pcs) (metal = Mn, Fe, Cu, and Mg) and metal-free Pc thin films of 1-monolayer (ML) thickness on an Fe(100) substrate were investigated using spin-polarized metastable deexcitation spectroscopy (SPMDS). The surface density-of-states (SDOS) of these Pcs observed in MDS was almost identical, and thus, insensitivity of the Pc electronic structure to the variation of the central metal atoms is indicated. On the other hand, the spin asymmetry in the SPMDS measurements exhibited noticeable differences among Pcs. These results are discussed from the viewpoint of the Pcs electronic structure calculated by a discrete variational X α method. The fact that differences are found in the spin asymmetry but not in SDOS among Pcs indicates an important role of the central metal atoms for spin polarization.

The role of interfaces in organic spin valves revealed through spectroscopic and transport measurements

“…Suzuki et al [19,20] performed the first measurement of the spin-polarization of metal pththalocyanines (abbreviated as M-Pc) on magnetized Fe(100) surfaces. Using spinpolarized metastable de-excitation spectroscopy they measured the electronic structure and spin-asymmetry for one monolayer of Mn, Fe, Cu, and Mg-Pc adsorbed on Fe(100).…”

Recent progress in organic spintronics

“…This has been studied in some detail for various π-conjugated molecules adsorbed on ferromagnetic surfaces. The most common experimental techniques to probe the interface electronic and magnetic structure are x-ray magnetic circular dichroism (XMCD) [93][94][95], spin-polarized scanning tunneling microscopy (SP-STM) [90,[96][97][98], spin-polarized metastable de-excitation spectroscopy(SP-MDS) [99][100][101], spin-polarized ultraviolet photoelectron spectroscopy (SP_UPS) [102][103][104], and spin-resolved two-photon photoemission (SR-2PPE) [77]. Modeling is typically done with density functional theory (DFT) [89,95,97,98,[104][105][106][107][108][109].…”

“…with a flat ring structure) π-conjugated molecules have been studied. In particular, metal-phthalocyanines (Pc's) and porphyrins have received a considerable amount of attention [89,93,96,97,99,[103][104][105]107]. The metal ions in these metallo-organic molecules typically have unpaired spins, which are found to couple to the ferromagnetic substrate via the exchange interaction.…”

The study of organic semiconductor/ferromagnet interfaces in organic spintronics: A short review of recent progress

“…They first measured the spin polarization of metal (Mn, Fe, Cu, and Mg) and metal-Free phthalocyanines on Fe (100), 57,58 and continued a study of pentacene on Fe (100). 59 All the spin asymmetry of these interfaces are positive (shown in Fig.…”