Disorder-induced Room Temperature Ferromagnetism in Glassy Chromites

• Published in: Scientific reports Vol. 4; no. 1; p. 4686
• Main Authors: Araujo, C. Moyses, Nagar, Sandeep, Ramzan, Muhammad, Shukla, R., Jayakumar, O. D., Tyagi, A. K., Liu, Yi-Sheng, Chen, Jeng-Lung, Glans, Per-Anders, Chang, Chinglin, Blomqvist, Andreas, Lizárraga, Raquel, Holmström, Erik, Belova, Lyubov, Guo, Jinghua, Ahuja, Rajeev, Rao, K. V.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.04.2014; Nature Publishing Group
• Subjects: 119/118; 639/766; 639/766/119; Chromium; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Humanities and Social Sciences; Lasers; MATERIALS SCIENCE; multidisciplinary; Physics; Science; Science & Technology - Other Topics; Temperature; Temperature effects; Thin films
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep04686

We report an unusual robust ferromagnetic order above room temperature upon amorphization of perovskite [YCrO 3 ] in pulsed laser deposited thin films. This is contrary to the usual expected formation of a spin glass magnetic state in the resulting disordered structure. To understand the underlying physics of this phenomenon, we combine advanced spectroscopic techniques and first-principles calculations. We find that the observed order-disorder transformation is accompanied by an insulator-metal transition arising from a wide distribution of Cr-O-Cr bond angles and the consequent metallization through free carriers. Similar results also found in YbCrO 3 -films suggest that the observed phenomenon is more general and should, in principle, apply to a wider range of oxide systems. The ability to tailor ferromagnetic order above room temperature in oxide materials opens up many possibilities for novel technological applications of this counter intuitive effect.