Magnetic Relaxation and Memory Effect in Nickel-Chromium Cyanide Nanoparticles

The low temperature dynamics of a magnetic nanoparticle system $Ni_3[Cr(CN)_6]_2$ with an average nanoparticles size of 4 nm was studied. Using different temperature and field protocols memory phenomena were studied by the DC magnetization and magnetic relaxation measurements of the system at temperatures below $T_m$ = 19 K. Aging experiments show an absence of any waiting time dependence in the magnetization relaxation due to a field change after zero field and field cooling. This observation discriminates the dynamics of the system from the behaviour of a classical spin-glass.