[18p-PB1-1~73] 10 Spintronics and Magnetics (Poster)

▲ [18p-PB1-52] Ir substitution site analysis of Corundum-type oxide films by extended X-ray absorption fine structure

〇Tomohiro Nozaki¹, Satya Prakash Pati¹, Yohei Shiokawa¹, Motohiro Suzuki², Toshiaki Ina², Muftah Al-Mahdawi¹, Sujun Ye¹, Masashi Sahashi^1,3 (1.Tohoku Univ., 2.JASRI, 3.ImPACT)

Keywords:antiferromagnet, X-ray absorption fine structure, Corundum

Cr₂O₃ and α-Fe₂O₃ are Corundum-type oxide antiferromagnets. Cr₂O₃ is a well-known magnetoelectric material and attract much attentions as an electrically controllable antiferromagnet. α-Fe₂O₃ is a high Néel temperature antiferromagnet (T_N ~ 950 K), which has a spin reorientation transition called Morin transition. We’ve been reported the enhancement of Morin transition temperature (thus enhancement of perpendicular magnetic anisotropy (PMA)) for α-Fe₂O₃ by tiny amount of Ir-doping. In contrast, we didn’t observe a distinguish change in PMA for Cr₂O₃ by Ir-doping. To investigate the difference, in this study, we tried to identify the Ir-substitution site in both Cr₂O₃ and α-Fe₂O₃ from extended X-ray absorption fine structure (EXAFS) analysis.
Ir-doped Cr₂O₃ and α-Fe₂O₃ films were fabricated on Al₂O₃ (0001) substrate by a reactive sputtering method. We simulated radial distribution function |χ(R)| of Ir L₃ edge with three different substitution site; 1) cation (Cr or Fe) site, 2) O-site, and 3) interstitial-site. Then we fitted experimentally obtained |χ(R)| by the three simulation results. The fitting results indicate that Ir most likely substitute cation site of both Cr₂O₃ and α-Fe₂O₃, rather than interstitial-site and O-site.