Alをwedge状に形成した強磁性トンネル接合の磁気抵抗効果

抄録

Ferromagnetic tunneling 80NiFe/Co/Al oxide/Co junctions with various Al oxide thicknesses were fabricated. To prepare Al oxide, a wedge-shaped piece of pure Al was sputtered without exposure to air. The surface roughness of the unexposed samples was quite small, while that of a sample with an air-leak tended to grow larger with increasing oxidization time and also d_Al. The tunneling magnetoresistive effect (TMR) was observed at an Al thickness of about 9 Å for exposed junctions. Below this thickness, the barrier height estimated from the I-V curve decreased. On the other hand, the barrier height and thickness were roughly constant for junctions with d_Al>9 Å. This indicated that the metallic Al could exist, causing a reduction in the TMR.