From Ferrimagnetism to spin-glass behavior in alkali- and rare-earth metal crichtonites.

In this work, nine new synthetic alkali- and rare-earth metal crichtonite-type compounds with AB₃C₁₈O₃₈ general formula are presented. The effect on the magnetic properties as consequence of the substitution of divalent and trivalent cations in the A site, as well as the introduction of iron at the B and C sites is studied. Ferrimagnetic behavior was identified in the crichtonites CaMn₃Ti₁₈O₃₈, BaMn₃Ti₁₈O₃₈ and CaFe₃Ti₁₈O₃₈, which changes to a spin-glass type for the BaMn₃Ti₁₄Fe₄O₃₈ and A-trivalent REMn₃Ti₁₈O₃₈ (RE = La, Ce and Nd), LaFe₃Ti₁₈O₃₈ and LaMn₃Ti₁₃Fe₅O₃₈. A comprehensive comparison of the AC and DC magnetic measurements for whole series along with the FiM structure obtained by neutron powder diffraction is discussed. These results will expand the comprehension on this almost unexplored magnetic family of compounds.