Issue 8, 2010

Experimental and theoretical investigations on magnetic behavior of (Al,Co) co-doped ZnOnanoparticles

Abstract

We present the structural and magnetic properties of Zn0.95−xCo0.05AlxO (x = 0.0 to 0.1) nanoparticles, synthesized by a novel sol–gel route followed by pyrolysis. Powder X-ray diffraction data confirms the formation of a single phase wurtzite type ZnO structure for all the compositions. The Zn0.95Co0.05O nanoparticles show diamagnetic behavior at room temperature. However, when Al is co-doped with Co with x = 0.0 to 0.10 in Zn0.95−xCo0.05AlxO, a systematic increase in ferromagnetic moment is observed up to x = 0.07 at 300 K. Above x = 0.07 (e.g. for x = 0.10) a drastic decrease in ferromagnetic nature is observed which is concomitant with the segregation of poorly crystalline Al rich ZnO phase as evidenced from TEM studies. Theoretical studies using density functional calculations on Zn0.95−xCo0.05AlxO suggest that the partial occupancy of S2 states leads to an increased double exchange interaction favoring the ferromagnetic ground states. Such ferromagnetic interactions are favorable beyond a threshold limit. At a high level doping of Al, the exchange splitting is reduced, which suppresses the ferromagnetic ordering.

Graphical abstract: Experimental and theoretical investigations on magnetic behavior of (Al,Co) co-doped ZnO nanoparticles

Article information

Article type
Paper
Submitted
17 Mar 2010
Accepted
21 Apr 2010
First published
03 Jul 2010

Nanoscale, 2010,2, 1505-1511

Experimental and theoretical investigations on magnetic behavior of (Al,Co) co-doped ZnO nanoparticles

O. D. Jayakumar, S. N. Achary, C. Sudakar, R. Naik, H. G. Salunke, R. Rao, X. Peng, R. Ahuja and A. K. Tyagi, Nanoscale, 2010, 2, 1505 DOI: 10.1039/C0NR00195C

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