Magnetic Susceptibility of NiO Nanoparticles
  Nickel oxide nanoparticles of different sizes are prepared and characterized by x-ray diffraction and transmission electron microscopy. A.C. susceptibility measurements as a function of temperature are carried out for various particle sizes and frequencies. We find that the behavior of the system is spin glass like. 
S.D. Tiwari and K.P.Rajeev