Full Bulk Spin Polarization and Intrinsic Tunnel Barriers at the Surface of Layered Manganites

Abstract

The affect of full bulk spin polarization and intrinsic tunnel barriers on the surface of layered manganites were studied using a combination of surface-sensitive x-ray and tunnelling process. The surface bilayer of air-cleaved layered manganites forms an antiferromagnetic insulating nanoskin composed of a single bilayer unit. It was shown that for the quasi-two-dimensional bilayer manganites the outermost Mn-O bilayer is affected while the next bilayer displays the full spin polarization of the bulk. The results show that the outermost bilayer act as an intrinsic barrier between the fully spin-polarized bilayer beneath and a subsequently deposited ferromagnetic counterelectrode.