Magnetic properties of Fe1-xCoxCr2S4

We designed a series of samples with Co substitution (Fe1-xCoxCr2S4, 0 <= x <= 1) and studied the Co doping effect in FeCr2S4. Spin glass transitions are observed in lower temperature regions and ferrimagnetic transitions are observed in higher temperature regions. The paramagnetic-ferrimagnetic transition temperature (T-C) increases with the amount of Co substitution. In order to clarify the magnetic character at the transition point, a critical exponent was obtained at about T-C. The exponent changes from Ising to Heisenberg as x increases. (C) 2006 American Institute of Physics.