Magnetism of Quantum-Classical Ferrimagnetic Chains Showing Alternate Heisenberg Coupling: Application to MnCu (Obp)(H₂O)₃, H₂O

Abstract

For a long time considerable litterature has been devoted to one-dimensional spin systems. The possibility of exactly solving various non trivial cases has been a strong motivation in this field. More recently the increasing number of new compounds showing quasi one-dimensional magnetic behavior gave a further impulsion to this subject. In the past, mainly so-called ferromagnetic and antiferromagnetic chains were considered from the point of view of their static properties¹. Then, dynamic properties were considered², and later on much attention was paid to ferrimagnetic chains,³ showing two types of alternating cations. A large variety of situations are involved in this last category, giving rise to new specific problems⁴. In the present article we are concerned with the static magnetic properties of a large class of ferrimagnetic chains defined by the following two conditions:-i) Two types of cations alternate along the chain. One of them, at least, must be characterized by a spin number large enough to be treated classically; ii) The hamiltonian is fully isotropic (Heisenberg coupling, no spin-lattice anisotropy) within the spin space.