Influence of cooling field on field induced magnetic states in Ca3Co2O6 compound.

Manifold degeneracy in the zero field cooled (ZFC) state of the Ising like spin system, Ca 3 Co 2 O 6 , is progressively alleviated by magnetic field (H) at low temperature (T). Field excursion after ZFC stabilizes ferrimagnetic (FIM) state above T sf ~7K which converts to ferromagnetic (FM) state at high-H. Whereas, various metastable states have been created by H excursion of degenerate ZFC state below T sf and finally it switches to FM state. In contrast, field cooling at 5kOe supports stable FIM ordering for all temperatures in low fields, which converts to the FM state at increasingly higher-H with decrease in T. This thermomagnetic irreversibility (TMI) below ~7K indicates non-ergodic nature of the ZFC state and it persists till the system fully saturates. It is obvious that both the hindered kinetics of H-T induced first order intermediate phase to FIM transformation and interplay of different interchain interactions like 1st nearest neighbor (nn) and 2nd nn with thermal energy are playing a crucial role in appearance of such type of TMI in this spin system. [ABSTRACT FROM AUTHOR]