抄録
The magnetic phase transition of the mixed crystals of nickel and magnesium hydroxides, NipMg(1−p)(OH)2, as randomly diluted magnets was investigated by measurements of the susceptibilities. The critical curve (phase transition temperatures versus concentrations, p) shows a terraced form in the concentration region below p∼0.4, which might reflect the quasi-two dimensionality of Ni(OH)2. The critical concentration, pc, is estimated as about 0.1. Furthermore, the dilution of Ni(OH)2 by Mg(OH)2 changes the values of θ⁄T°max and χM°(T=0)⁄χM°max, and the shape of the peak of the susceptibility, where T°max is the temperature at which the susceptibility, χM° , has a peak value, χM°max. These changes are interpreted as a result of the change of the spin arrangement in an ordered state depending on the concentration, p.
