Magnetoresistance of 3d transition-metal-doped epitaxial ZnO thin films

✍ Scribed by Zhengwu Jin; K Hasegawa; T Fukumura; Y.Z Yoo; T Hasegawa; H Koinuma; M Kawasaki

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 100 KB
• Volume: 10
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(01)00094-7

✦ Synopsis

Epitaxial ZnO thin ÿlms co-doped with 3d transition metal (TM) (TM = Cr, Mn, Fe, Co, Ni and Cu) and 1 mol% Al were fabricated as a series of oxide-diluted magnetic semiconductors by pulsed-laser-deposition method. Magnetoresistance (MR) of the ÿlms was measured to investigate the s-d exchange interaction between the conducting s electron spins and the d electron spins localized at the magnetic TM impurities. A variety of MR behaviors were observed depending on the di erent TM impurities. It is deduced that the negative MR behavior in the vicinity of zero ÿeld is originated from an electron weak-localization e ect. Caused by the s-d exchange interaction, the increase of Thomas-Fermi radius Rs and the decrease of spin-disorder scattering with increasingly aligned spins of the TM ion impurities are responsible respectively for the positive and negative MR in the higher magnetic ÿled.