High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process
Although an enhanced magnetoresistance (MR) has been observed in many Co2-based Heusler alloys by promoting their structural ordering from B2 to L21 by post-annealing at higher temperatures (Tann > 500 °C), it is desirable to search for other Heusler alloys that crystallize in L21-order below 300...
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2022-09-01
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| Series: | APL Materials |
| Online Access: | http://dx.doi.org/10.1063/5.0117593 |
| _version_ | 1797984958166335488 |
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| author | Varun Kumar Kushwaha Yuya Sakuraba Tomoya Nakatani Taisuke Sasaki Ivan Kurniawan Yoshio Miura Hiroo Tajiri Kazuhiro Hono |
| author_facet | Varun Kumar Kushwaha Yuya Sakuraba Tomoya Nakatani Taisuke Sasaki Ivan Kurniawan Yoshio Miura Hiroo Tajiri Kazuhiro Hono |
| author_sort | Varun Kumar Kushwaha |
| collection | DOAJ |
| description | Although an enhanced magnetoresistance (MR) has been observed in many Co2-based Heusler alloys by promoting their structural ordering from B2 to L21 by post-annealing at higher temperatures (Tann > 500 °C), it is desirable to search for other Heusler alloys that crystallize in L21-order below 300 °C, as the maximum Tann is restricted for processing devices. For Co2MnZ (Z = Ge, Sn) Heusler alloys, an L21-order is expected to appear even in the as-deposited state or by a low-temperature annealing process due to their very high L21 to B2-order transition temperature (>1500 K). Here, epitaxial Co2MnZ films were grown on MgO (001) substrate at room temperature (RT) and post-annealed at Tann = 200–500 °C. Interestingly, as-sputtered films exhibit L21-ordering, which improves systematically upon increasing Tann. The spin-polarization of electric current (β) was estimated at RT using nonlocal spin-valve (NLSV) devices by measuring the spin-accumulation signal in a copper (Cu) channel. It was found that at Tann = 300 °C, the β value of Co2MnGe films is higher (∼0.65) than that of Co2FeGe0.5Ga0.5 films due to a higher degree of L21-order, which makes the Co2MnGe alloy a promising ferromagnetic electrode for spintronic device applications. |
| first_indexed | 2024-04-11T07:11:17Z |
| format | Article |
| id | doaj.art-6c1de6b0cfe94cb9ad99a9b6f1c79a44 |
| institution | Directory Open Access Journal |
| issn | 2166-532X |
| language | English |
| last_indexed | 2024-04-11T07:11:17Z |
| publishDate | 2022-09-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | APL Materials |
| spelling | doaj.art-6c1de6b0cfe94cb9ad99a9b6f1c79a442022-12-22T04:38:12ZengAIP Publishing LLCAPL Materials2166-532X2022-09-01109091119091119-710.1063/5.0117593High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing processVarun Kumar Kushwaha0Yuya Sakuraba1Tomoya Nakatani2Taisuke Sasaki3Ivan Kurniawan4Yoshio Miura5Hiroo Tajiri6Kazuhiro Hono7National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanJapan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, JapanNational Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanAlthough an enhanced magnetoresistance (MR) has been observed in many Co2-based Heusler alloys by promoting their structural ordering from B2 to L21 by post-annealing at higher temperatures (Tann > 500 °C), it is desirable to search for other Heusler alloys that crystallize in L21-order below 300 °C, as the maximum Tann is restricted for processing devices. For Co2MnZ (Z = Ge, Sn) Heusler alloys, an L21-order is expected to appear even in the as-deposited state or by a low-temperature annealing process due to their very high L21 to B2-order transition temperature (>1500 K). Here, epitaxial Co2MnZ films were grown on MgO (001) substrate at room temperature (RT) and post-annealed at Tann = 200–500 °C. Interestingly, as-sputtered films exhibit L21-ordering, which improves systematically upon increasing Tann. The spin-polarization of electric current (β) was estimated at RT using nonlocal spin-valve (NLSV) devices by measuring the spin-accumulation signal in a copper (Cu) channel. It was found that at Tann = 300 °C, the β value of Co2MnGe films is higher (∼0.65) than that of Co2FeGe0.5Ga0.5 films due to a higher degree of L21-order, which makes the Co2MnGe alloy a promising ferromagnetic electrode for spintronic device applications.http://dx.doi.org/10.1063/5.0117593 |
| spellingShingle | Varun Kumar Kushwaha Yuya Sakuraba Tomoya Nakatani Taisuke Sasaki Ivan Kurniawan Yoshio Miura Hiroo Tajiri Kazuhiro Hono High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process APL Materials |
| title | High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process |
| title_full | High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process |
| title_fullStr | High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process |
| title_full_unstemmed | High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process |
| title_short | High L21-atomic ordering and spin-polarization in Co2MnZ (Z = Ge, Sn) Heusler thin films with low-temperature annealing process |
| title_sort | high l21 atomic ordering and spin polarization in co2mnz z ge sn heusler thin films with low temperature annealing process |
| url | http://dx.doi.org/10.1063/5.0117593 |
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