Disorder-induced Room Temperature Ferromagnetism in Glassy Chromites

作者：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; Lizarraga Raquel; Holmstroem Erik; Belova Lyubov; Guo Jinghua; Ahuja Rajeev; Rao K V^*

来源：Scientific Reports, 2014, 4(1): 4686.

DOI：10.1038/srep04686

We report an unusual robust ferromagnetic order above room temperature upon amorphization of perovskite [YCrO3] 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 YbCrO3-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.

• 出版日期2014-4-15