Structural Characterization and Magnetic Order in Phenoxy-Substituted Divalent Metal Phosphonate Langmuir–Blodgett Films

Metal phosphonate Langmuir–Blodgett (LB) films of an alkoxyphenyl-substituted phosphonic acid (P4A) have been prepared with the divalent metals Mn2+ and Cd2+. Structural characterization with infrared spectroscopy, XPS, and X-ray diffraction shows that the films contain the inorganic continuous lattice of known layered solid-state metal phosphonates with formula M (O3PR)H2O. Magnetic characterization of the Mn-P4 LB film consists of EPR and magnetometry measurements. The Mn-P4 LB film undergoes a transition to a long-range, canted antiferromagnetic state below 14.8±0.2 K and is only the second example of a continuous lattice LB film to exhibit spontaneous magnetization. These results demonstrate that it is possible to prepare metal phosphonate LB films of functionalized organophosphonic acids while retaining both the inorganic continuous lattice structure and magnetic exchange pathways of the known solid-state metal organophosphonates.