Relaxation phenomena in super spin glass nanoparticle manganite La0.7Ca0.3MnO3

Investigation of complex, nonequilibrium dynamics of super spin glass nanoparticle La0.7Ca0.3MnO3 sample was conducted through the comprehensive set of magnetization relaxation measurements. It comprised measurements of thermoremanent and zero-field cooled magnetization time decay under various temperature and field conditions, as well as study of the ageing effect for different waiting times. A variety of theoretical models dealing with nonequilibrium dynamics in spin glasses was successfully implemented in the description of experimentally observed relaxation phenomena. Collective behaviour observed at low temperatures and intermediate magnetic fields was found to be the consequence of the random orientation of easy axes and significant dipolar interactions between nanoparticle moments.