Dynamic magnetic properties of the colossal magnetoresistance ferromagnet ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_3$ have been explored by ac-susceptibilities and dc-magnetization measurements. The system orders magnetically below $T_c\approx 235$ K with a large difference between zero-field-cooled and field-cooled magnetization in low fields. Both the in-phase and out-of-phase components of the susceptibility are frequency dependent in the ferromagnetic phase. The system shows long-time relaxation of the zero-field-cooled magnetization and age-dependent effects at all temperatures below $T_c.$ The observed results evidence the existence of frustration and magnetic disorder in ${\mathrm{Nd}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_3,$ but there is no indication of a re-entrant phase transition down to 5 K.

• Received 29 November 1999

DOI:https://doi.org/10.1103/PhysRevB.62.1027