Anomalous low-field magnetization in La2/3Ca1/3MnO3 near the critical point: Stable clusters?

Publisher Website
Google Scholar
Abstract
The magnetic behavior of bulk La 2/3 Ca 1/3 MnO 3 (T C =267 K ) at low fields in the paramagnetic phase was studied. Near T C (T−T C <30 K ) we find a sequence of steplike features in the effective Curie constant C(T)=M(T−T C )/H at well defined temperatures and intermediate plateaus, accompanied by temperature hysteresis. On approaching T C , the C values at each plateau follow a geometrical progression, with the effective spin S doubled at each step. The first plateau gives S=5.5, corresponding to a cluster of three Mn 3+ ions sharing one extra hole. This suggests that close to T C short range magnetic order at low fields develops hierarchically through a series of most stable cluster states.