Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 3: Spin-Dependent Transport Phenomena I
MA 3.2: Vortrag
Montag, 27. März 2006, 10:30–10:45, HSZ 103
Magnetic tunnel junctions with MgO barriers — •Volker Drewello, Xinli Kou, Jan Schmalhorst, Andy Thomas, and Günter Reiss — Bielefeld University, Nano Device Group, 33615 Bielefeld
Recently, there has been much excitement about the high tunneling magnetoresistance (TMR) values observed in magnetic tunnel junctions (MTJs) with crystalline magnesium oxide (MgO) barriers. These MTJs show vary large TMR values compared to those with amorphous aluminum oxide barriers.
We have investigated the TMR in MTJs with MgO barriers and several different electrode materials. The MTJs are prepared at ambient temperature in our DC magnetron sputtering chamber with a base pressure of 1.0× 10−7 mbar. In this process the lower electrode is covered with a thin layer of Magnesium (Mg) to prevent oxidation during the sputtering of MgO. Then, the latter is directly sputtered on the Mg layer.
The different FM/Mg/MgO/FM layer systems show TMR values of up to about 120% depending on the electrode material. Furthermore, the thickness of the Mg and the MgO layers as well as the annealing temperature have been optimized yielding high TMR ratios. The results are compared with standard Alumina junctions.