Variation in the properties of the interface in a CoFeB∕MgO∕CoFeB tunnel junction during thermal annealing
Variation in the quality of the interface in a CoFeB∕MgO∕CoFeB tunnel junction during thermal annealing was investigated using x-ray photoemission spectroscopy. The formation of B oxide and the reduction of Fe oxide at the bottom interface after thermal annealing near Ta=300°C were found to enhance...
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Veröffentlicht in: | Applied physics letters 2007-09, Vol.91 (10) |
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Hauptverfasser: | , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Variation in the quality of the interface in a CoFeB∕MgO∕CoFeB tunnel junction during thermal annealing was investigated using x-ray photoemission spectroscopy. The formation of B oxide and the reduction of Fe oxide at the bottom interface after thermal annealing near Ta=300°C were found to enhance the tunneling magnetoresistance ratio significantly. At the same time, an asymmetry of the conductance (dV∕dI) in the bias polarity and a local minimum of conductance in a positive bias state were measured which were attributed to the presence of a minority state at the bottom interface. The authors believe that the existence of the Bloch state was also responsible for the failure of the application of the Brinkman-Dynes-Rowell or Simmons models to the CoFeB∕MgO∕CoFeB junction. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.2779915 |