Abstract
Magnetic tunnel junctions with barrier thicknesses of either 1.6 or 2.4 nm have been fabricated from epitaxially grown La0.8Sr0.2MnO3/SrTiO3/La0.8Sr0.2MnO3 trilayers. For the junctions with 1.6-nm-thick SrTiO3, tunneling magnetoresistance (TMR) as large as 150% was observed at 5 K. A small TMR was observed even at 270 K, which is close to the ferromagnetic Curie temperature (290 K) of the La0.8Sr0.2MnO3 film. Besides tunneling conduction, parallel semiconduction through the SrTiO3 barrier appeared to exist, and became dominant at high temperatures, reducing the TMR ratio and operating temperature, especially for thicker SrTiO3 barriers. The SrTiO3 barrier thickness is the key to improving TMR characteristics, and fabricating a sufficiently thin and uniform barrier layer is essential for achieving a large TMR and a high operating temperature.
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Obata, T., Manako, T., shimakawa, Y. et al. Magnetoresistance in Tunnel Junctions Made of Epitaxially Grown Manganate Films with 1.6-nm-Thick Barriers. Journal of Electroceramics 4, 427–432 (2000). https://doi.org/10.1023/A:1009924307232
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DOI: https://doi.org/10.1023/A:1009924307232