Phenomenological model for the remanent magnetization of dilute quasi-one-dimensional antiferromagnets

We present a phenomenological model for the remanent magnetization at low temperatures in the quasi-one-dimensional dilute antiferromagnets (CH3NH3)Mn1-xCdxCl3.2H(2)O and (CH3)(2)NH2Mn1-xCdxCl3.2H(2)O. The model assumes the existence of uncompensated magnetic moments induced in the odd-sized segments generated along the Mn2+ chains upon dilution. These moments are further assumed to correlate ferromagnetically after removal of a cooling field. Using a (mean-field) linear-chain approximation and a reasonable set of model parameters, we are able to reproduce the approximate linear temperature dependence observed for the remanent magnetization in the real compounds.