▎ 摘　　要

Nickel-adsorbed graphene was prepared by first synthesizing graphite oxide ( GO) by modified Hummers' method and then reducing a solution containing both GO and Ni2+. Energy dispersive X-ray spectroscopy analysis showed 31 at. % nickel was present. Magnetization measurements under both dc and ac magnetic fields were carried out in the temperature range 2K to 300 K. The zero field cooled and field cooled magnetization data showed a pronounced irreversibility at a temperature around 20 K. The analysis of the ac susceptibility data was carried out by both Vogel-Fulcher as well as power law. From dynamic scaling analysis, the microscopic flipping time tau(0) similar to 10(-13)s and critical exponent z nu = 5.9 +/- 0.1 were found, indicating the presence of conventional spin glass in the system. The spin glass transition temperature was estimated as 19.5 K. Decay of thermoremanent magnetization was explained by stretched exponential function with a value of the exponent as 0.6. From the results, it is concluded that nickel adsorbed graphene behaves like a spin-glass. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4774062]