Presentation Information
[P1-73]Effect of Ir addition on the crystal structure and magnetic properties for Mn-Ga thin films
*Yuto Yamazaki1, Masaaki Doi1, Toshiyuki Shima1 (1. Tohoku Gakuin University (Japan))
Keywords:
Mn-Ga alloy,Ir addition,magneto-crystalline anisotropy,coercivity,thin film
High perpendicular magnetic anisotropy is required in spintronics devices, and among ferromagnetic alloys, MnGa alloy films are considered a promising material as they fully satisfy this requirement [1]. Recently, the detailed effects of magneto-crystalline anisotropy in Mn-Ga alloys have been reported using first-principles calculations, and it has been shown that the addition of small amount of Ir can significantly improve the magneto-crystalline anisotropy of Mn-Ga alloys [2]. In this study, Mn-Ga alloy thin films with varying amount of Mn and Ir were prepared to improve the magneto-crystalline anisotropy, and their crystal structure and magnetic properties were investigated in detail. All samples were prepared on MgO (100) single-crystal substrates using an ultra-highvacuum magnetron sputtering system. The base pressure of the deposition chamber was approximately 5.0 × 10-8 Pa and Ar gas was maintained at a pressure of 0.135 Pa during the sputtering process. Before deposition, the substrate was heated at 600ºC for 30 minutes for cleaning, followed by the deposition of 70 nm of Ir-doped Mn-Ga thin film at 500ºC. The amount of Mn in the Mn-Ga alloy was varied between 49.7 and 64.9 at.%. After deposition, the substrate was cooled down to room temperature and capped with a 10 nm thick Cr layer to prevent oxidization. The crystal structure was determined using an X-ray diffractometer (XRD), and the magnetic properties were evaluated using a superconducting quantum interference device (SQUID) magnetometer. From the XRD patterns, the (001) and (002) peaks of the L10 structure were clearly observed when the Mn content was 49.7 at.%, and the (002) and (004) peaks of the D022 structure were clearly observed between 53.8 and 64.9 at.%. When Ir was added to the Mn-Ga alloy thin films, their main peak positions shifted to the high-angle side in the case of compositions showing the L10 structure and to the low-angle side in the case of composition regions showing the D022 structure, and the intensity of their peaks was also reduced. The magnetization curves show that the addition of Ir decreases the saturation magnetization of the Mn-Ga thin film both in-plane and perpendicular direction to the film plane, while the coercive force increases. In the Mn59.9Ga40.1 thin film sample, the magneto-crystalline anisotropy increased when the amount of Ir was 4.0 at.%, confirming that the coercive force and magneto-crystalline anisotropy of the Mn-Ga thin film were improved by Ir addition.
References
1) Yumei Zhang, Wen Zhang, Mengyao Ning, Lingli Chen, Haibo Li, Sur. Sci., 542, 148585 (2021).
2) Lukas Wollmann, Stanislav Chadov, Jürgen Kübler, and Claudia Felser, Rev. B, 92, 064417 (2015).
References
1) Yumei Zhang, Wen Zhang, Mengyao Ning, Lingli Chen, Haibo Li, Sur. Sci., 542, 148585 (2021).
2) Lukas Wollmann, Stanislav Chadov, Jürgen Kübler, and Claudia Felser, Rev. B, 92, 064417 (2015).