We review the progress towards developing epitaxial graphene as a material for carbon electronics. In particular, we discuss improvements in epitaxial graphene growth, interface control and the understanding of multilayer epitaxial graphene's (MEG's) electronic properties. Although graphene grown on both polar faces of SiC will be discussed, our discussions will focus on graphene grown on the C-face of SiC. The unique properties of C-face MEG have become apparent. These films behave electronically like a stack of nearly independent graphene sheets rather than a thin Bernal stacked graphite sample. The origins of multilayer graphene's electronic behaviour are its unique highly ordered stacking of non-Bernal rotated graphene planes. While these rotations do not significantly affect the inter-layer interactions, they do break the stacking symmetry of graphite. It is this broken symmetry that leads to each sheet behaving like isolated graphene planes.

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We investigate the origin of purported "spin accumulation" signals observed in local "threeterminal" (3T) measurements of ferromagnet/insulator/n-Si tunnel junctions using inelastic electron tunneling spectroscopy (IETS). Voltage bias and magnetic field dependences of the IET spectra were found to account for the dominant contribution to 3T magnetoresistance signals, thus indicating that it arises from inelastic tunneling through impurities and defects at junction interfaces and within the barrier, rather than from spin accumulation due to pure elastic tunneling into bulk Si as has been previously assumed.Creating, controlling, and detecting spin-polarized electron currents in nonmagnetic materials is the first step toward integrating spintronic devices with new functionalities and energy efficiency [1, 2] such as spin transistors [3] and spin-based logic circuits [4], which make use of the electron's spin degree of freedom instead of its charge. Silicon (Si) has low spin-orbit coupling and long spin lifetime [5], making it an excellent candidate for spin-enabled devices, but the conductivity mismatch between semiconductors and ferromagnetic metal (FM) spin sources prohibits ohmic electrical spin injection and detection in this material [6]. To overcome this difficulty, ballistic hot electron injection and detection techniques were used to finally achieve long-distance spin transport and coherent precession in intrinsic Si in 2007 [5,7]. Using a tunneling barrier approach [8], four-terminal nonlocal measurements of open-circuit voltage at ferromagnetic contacts [9] were subsequently demonstrated in degenerately doped Si at low temperature [10] and at room temperature in 2011. [11] During this time, there were also several claims that "accumulation" of spin-polarized electron density had been measured in highly doped Si [12, 13] using a local, three terminal (3T) geometry (schematically shown in Fig. 1(a)) at and beyond room temperature. This setup is intended to employ the same ferromagnetic contact for simultaneous injection and detection with signals dependent on magnetic field-induced spin precession and dephasing ("Hanle effect"). These reports present magnetoresistance (MR) in kOersted magnetic fields on the order of 0.1% (typically millivolt changes on one volt background at milliAmp constant current [12][13][14][15]), far exceeding voltage signals from non-local experiments [11]. The spin lifetimes (τ s ) extracted from their magnetic field linewidths are two orders of magnitude lower than those measured by electron spin resonance (ESR) [16,17] under similar conditions and show little dependence on the carrier type [18], the doping of the semiconductor in the transport channel, or temperature [12,13]; the signal width also remains invariant in metals with considerably different spin-orbit interaction strength [19]. Additionally, the claimed lifetime and signal magnitude are not self-consistent; a simple theoretical model of elas-

In this work we use LEEM, XPEEM and XPS to study how the excess Si at the graphene-vacuum interface reorders itself at high temperatures. We show that silicon deposited at room temperature onto multilayer graphene films grown on the SiC(0001) rapidly diffuses to the graphene-SiC interface when heated to temperatures above 1020• C . In a sequence of depositions, we have been able to intercalate ∼ 6 ML of Si into the graphene-SiC interface.

We report on the temperature dependence of the spin-pumping effect and the Gilbert damping in Co/Pt bilayers grown on Silicon oxide by measuring the change of the linewidth in a ferromagnetic resonance (FMR) experiment. By varying the Co thickness d(Co) between 1.5 nm and 50 nm we find that the damping increases inversely proportional to d(Co) at all temperatures between 300 K and 5 K, showing that the spin pumping effect does not depend on temperature. We also find that the linewidth increases with decreasing temperature for all thicknesses down to about 30 K, before leveling off to a constant, or even decreasing again. This behavior is similar to what is found in bulk ferromagnets, leading to the conclusion that in thin films a conductivity-like damping mechanism is present similar to what is known in crystals.