Origin of the broad three-terminal Hanle signals in Fe/SiO2/Si tunnel junctions.

Lorentzian-shaped broader three-terminal Hanle (B-3TH) signals are observed in Fe/SiO2/Si tunnel junction devices at 6-300 K. We propose a spin conducting model, which explains all the characteristics of our experimental results, such as field angle dependence and bias dependence of the B-3TH signals, as well as experimental results reported by other groups. It was found that the shape of the B- 3TH signals is determined by the spin depolarization at the Fe/SiO2 interface caused by local magnetic fields, unlike the conventional understanding. The shape of the B-3TH signals, including narrower and inverted Hanle signals, reflects the magnetic order of an ultrathin paramagnetic layer formed at the Fe/SiO2 interface. Our model provides a unified explanation of the B-3TH signals observed in threeterminal Hanle measurements. [ABSTRACT FROM AUTHOR]