Peculiar temperature dependence of magneto-optic Kerr rotation associated with antiferromagnetic–paramagnetic transition

• Published in: Japanese Journal of Applied Physics 2023-03, Vol.62 (SB), p.SB1002
• Main Authors: Ekawa, Hirofumi, Okano, Takashi, Huang, Oujin, Iino, Ion, Toyoki, Kentaro, Nakatani, Ryoichi, Kato, Takeshi, Shiratsuchi, Yu
• Format: Article
• Language: English
• Subjects: antiferromagnet; Antiferromagnetism; Chromium oxides; Incident light; Interference; Iridium; Kerr magnetooptical effect; magneto-optic Kerr effect; Neel temperature; Rotation; Temperature dependence; Thin films
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/ac8b8e

We investigate the magneto-optic Kerr effect in perpendicularly magnetized Pt/Co/Ir/Cr 2 O 3 /Pt thin films, associated with the antiferromagnetic–paramagnetic transition of the Cr 2 O 3 layer. The magneto-optic Kerr rotation angle ( θ K ) shows oscillatory behavior as a function of the photon energy of incident light owing to interference in the Cr 2 O 3 layer. The temperature dependence of θ K at 2.67 eV ( λ = 465 nm), at which the largest θ K is obtained, shows a sharp dip at 287.0 K. The dip temperature is similar to the reported Néel temperature for Cr 2 O 3 thin films. Although the θ K spectra measured at several temperatures are generally explained by the classical interference model, θ K is enhanced at 2.36–2.79 eV ( λ = 525–445 nm) close to the dip temperature. This peculiar enhancement in θ K is discussed on the basis of the anomaly in the optical parameters of the Cr 2 O 3 layer associated with the antiferromagnetic–paramagnetic transition.