Effect of the interface resistance of CoFe/MgO contacts on spin accumulation in silicon

We show direct evidence for importance of the interface resistance to electrically create large spin accumulation in silicon (Si). With increasing the thickness of the tunnel barrier in CoFe/MgO/n ⁺-Si devices, a marked enhancement of spin accumulation signals can be observed in the electrical Hanle-effect measurements. To demonstrate room-temperature detection of the spin signals in three-terminal methods, the influence of the spin absorption from Si into CoFe through a tunnel barrier should be taken into account.