Field induced spin transitions and large magnetoresistance in the quasi-one-dimensional magnet Ca/sub 3/Co/sub 2/O/sub 6/

The Co spin states on trigonal prisms and octahedral were clarified, and the large magnetoresistance during phase transitions induced by externally applied fields was obtained. The magnetic susceptibility of Ca/sub 3/Co/sub 2/O/sub 6/ single crystals were measured for varying temperatures. A second magnetic transition was observed to occur at T/sub c2/=12 K. Results reveal an intra-chain ferromagnetic ordering at T/sub c1/=23 K and a weak antiferromagnetic inter-chain coupling at T/sub c2/=12 K. The field induced phase transition from a ferrimagnetic to ferromagnetic state and the prominent magnetic hysteresis suggests that the sample behaves as an Ising-like antiferromagnetic triangular lattice.