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Tunnel magnetoresistance in epitaxial magnetic tunnel junctions using full-Heusler alloy Co2MnGe thin film and MgO tunnel barrier
| Title: | Tunnel magnetoresistance in epitaxial magnetic tunnel junctions using full-Heusler alloy Co2MnGe thin film and MgO tunnel barrier |
| Authors: | Marukame, Takao Browse this author | | Ishikawa, Takayuki Browse this author | | Matsuda, Ken-ichi Browse this author →KAKEN DB | | Uemura, Tetsuya Browse this author →KAKEN DB | | Yamamoto, Masafumi Browse this author |
| Issue Date: | 15-Apr-2006 |
| Publisher: | American Institute of Physics |
| Journal Title: | Journal of applied physics |
| Volume: | 99 |
| Issue: | 8 |
| Start Page: | 08A904-1 |
| End Page: | 08A904-3 |
| Publisher DOI: | 10.1063/1.2167063 |
| Abstract: | We fabricated fully epitaxial magnetic tunnel junctions (MTJs) using a Co-based full-Heusler alloy Co2MnGe (CMG) thin film as a lower electrode, an MgO tunnel barrier, and a Co50Fe50 upper electrode and investigated their tunnel magnetoresistance (TMR) characteristics. The microfabricated MTJs showed strongly temperature-dependent TMR characteristics with typical TMR ratios of 70% at 7 K and 14% at room temperature (RT). Furthermore, the TMR characteristics exhibited the following notable features in the bias voltage (V) dependence: (1) a cusplike V dependence within a range of similar to +/- 200 mV around V=0 at 7 K, which was smeared out at RT, and (2) a V dependence with pronounced asymmetry regarding the polarity, showing negative TMR ratios in a certain negative bias voltage range around -400 mV at both 7 K and RT (V was defined with respect to the lower CMG electrode). A possible transport mechanism leading to the notably asymmetric V dependence along with the negative TMR for a certain bias voltage region is direct tunneling that reflects the spin-dependent density of states of the CMG electrode. |
| Rights: | (C) 2006 American Institute of Physics. |
| Relation: | http://jap.aip.org/jap/top.jsp |
| Type: | article |
| URI: | http://hdl.handle.net/2115/13458 |
| Appears in Collections: | 情報科学院・情報科学研究院 (Graduate School of Information Science and Technology / Faculty of Information Science and Technology) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 丸亀 孝生
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