06 July - Electrically Induced Ferromagnetism at Room Temperature in Cobalt-Doped Titanium Dioxide

1. Today Peiman is presenting the following paper:

1. 
   

1. Science 27 May 2011: 
   Vol. 332 no. 6033 pp. 1065-1067 
   DOI: 10.1126/science.1202152

1. Y. Yamada¹,*, 
2. K. Ueno²,³,*, 
3. T. Fukumura³,⁴,†, 
4. H. T. Yuan⁵,⁶, 
5. H. Shimotani⁵,⁶, 
6. Y. Iwasa⁵,⁶, 
7. L. Gu², 
8. S. Tsukimoto²,
9. Y. Ikuhara²,⁷,⁸, and 
10. M. Kawasaki¹,²,⁵,⁶

The electric field effect in ferromagnetic semiconductors enables switching of the magnetization, which is a key technology for spintronic applications. We demonstrated electric field–induced ferromagnetism at room temperature in a magnetic oxide semiconductor, (Ti,Co)O₂, by means of electric double-layer gating with high-density electron accumulation (>10¹⁴ per square centimeter). By applying a gate voltage of a few volts, a low-carrier paramagnetic state was transformed into a high-carrier ferromagnetic state, thereby revealing the considerable role of electron carriers in high-temperature ferromagnetism and demonstrating a route to room-temperature semiconductor spintronics.