Study of the magnetization and magnetic anisotropy of the metal-radical complex of bis(hexafluoroacetylacetonato)manganese(II) with a trisnitroxide radical:

Abstract

A single crystal of the metal-radical complex , where is a trisnitroxide with a quartet ground state, was grown. The magnetization was measured along the principal crystallographic axes in the range 1.8-300 K. The compound was found to order ferrimagnetically at with collinear antiparallel alignment of the Mn and magnetic spins along the c-direction. The paramagnetic susceptibility was treated in the quantum-classical approximation by taking into account the weak positive exchange interaction between the Mn( 2) ions and one-dimensional ferrimagnetic chains, in which trimer molecules composed of one Mn( 1) and two 1/2 spins of different triradicals can be isolated. The anisotropy constants were evaluated and the anisotropy energy was estimated. Anisotropy of the paramagnetic susceptibility, which can be detected up to 55 K, was observed. The anisotropic effects are attributed both to the single-ion splitting of the Mn energy levels and the dipole-dipole interaction between the magnetic spins.