Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy
Magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy (PMA) are investigated as a function of annealing temperature (T anneal ) and annealing time for several capping layers. Magnetic properties in films capped by TaO x vary markedly with T anneal ; the sa...
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| Format: | Article |
| Language: | English |
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AIP Publishing
2020
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| Online Access: | https://hdl.handle.net/1721.1/128665 |
| _version_ | 1826190177729511424 |
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| author | Ueda, Kohei Tan, Aik Jun Beach, Geoffrey Stephen |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Ueda, Kohei Tan, Aik Jun Beach, Geoffrey Stephen |
| author_sort | Ueda, Kohei |
| collection | MIT |
| description | Magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy (PMA) are investigated as a function of annealing temperature (T anneal ) and annealing time for several capping layers. Magnetic properties in films capped by TaO x vary markedly with T anneal ; the saturation magnetization and coercivity vary progressively with increasing T anneal up to 300°C, and above that temperature, PMA is lost abruptly. By comparing the annealing temperature dependence for Co-dominated and Gd-dominated compositions close to the magnetization compensation point, the data are readily explained by preferential oxidation of Gd during annealing. When films are capped by a Ta/Pt bilayer, the film properties are stable up T anneal = 300 °C, indicating that oxidation at high temperatures is effectively blocked, but the abrupt loss of PMA for T anneal > 300 °C is still observed. X-ray diffraction measurement reveals that the amorphous structure of the films remains the same after high-temperature annealing that is sufficient to remove PMA, indicating that crystallization from the amorphous phase is not responsible for the lack of PMA. Instead, our results suggest that high annealing temperatures may cause segregation of Co and Gd atoms in the films, which reduces anisotropic pair-pair correlations responsible for the observed bulk PMA in the as-grown state. ©2018 Author(s). |
| first_indexed | 2024-09-23T08:36:16Z |
| format | Article |
| id | mit-1721.1/128665 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:36:16Z |
| publishDate | 2020 |
| publisher | AIP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1286652022-09-23T13:13:18Z Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy Ueda, Kohei Tan, Aik Jun Beach, Geoffrey Stephen Massachusetts Institute of Technology. Department of Materials Science and Engineering Magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy (PMA) are investigated as a function of annealing temperature (T anneal ) and annealing time for several capping layers. Magnetic properties in films capped by TaO x vary markedly with T anneal ; the saturation magnetization and coercivity vary progressively with increasing T anneal up to 300°C, and above that temperature, PMA is lost abruptly. By comparing the annealing temperature dependence for Co-dominated and Gd-dominated compositions close to the magnetization compensation point, the data are readily explained by preferential oxidation of Gd during annealing. When films are capped by a Ta/Pt bilayer, the film properties are stable up T anneal = 300 °C, indicating that oxidation at high temperatures is effectively blocked, but the abrupt loss of PMA for T anneal > 300 °C is still observed. X-ray diffraction measurement reveals that the amorphous structure of the films remains the same after high-temperature annealing that is sufficient to remove PMA, indicating that crystallization from the amorphous phase is not responsible for the lack of PMA. Instead, our results suggest that high annealing temperatures may cause segregation of Co and Gd atoms in the films, which reduces anisotropic pair-pair correlations responsible for the observed bulk PMA in the as-grown state. ©2018 Author(s). NSF (DMR-14-19807) NSF (NSF-ECCS-1408172) 2020-11-25T22:32:19Z 2020-11-25T22:32:19Z 2018-12 2018-08 2019-09-17T15:29:52Z Article http://purl.org/eprint/type/JournalArticle 2158-3226 https://hdl.handle.net/1721.1/128665 Ueda, Kohei et al., "Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy." AIP Advances 8, 12 (December 2018): 125204 ©2018 Authors en https://dx.doi.org/10.1063/1.5054164 AIP Advances Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf AIP Publishing American Institute of Physics (AIP) |
| spellingShingle | Ueda, Kohei Tan, Aik Jun Beach, Geoffrey Stephen Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title | Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title_full | Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title_fullStr | Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title_full_unstemmed | Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title_short | Effect of annealing on magnetic properties in ferrimagnetic GdCo alloy films with bulk perpendicular magnetic anisotropy |
| title_sort | effect of annealing on magnetic properties in ferrimagnetic gdco alloy films with bulk perpendicular magnetic anisotropy |
| url | https://hdl.handle.net/1721.1/128665 |
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