Structural characterization and magnetic order in phenoxy-substituted divalent metal phosphonate Langmuir-Blodgett films

Metal phosphonate Langmuir-Blodgett (LB) films of an alkoxyphenyl-substitut ed phosphonic acid (P4A) have been prepared with the divalent metals Mn2+ a nd Cd2+. Structural characterization with infrared spectroscopy, XPS, and X -ray diffraction shows that the films contain the inorganic continuous latt ice of known layered solid-state metal phosphonates with formula M(O3PR)H2O . Magnetic characterization of the Mn-P4 LB film consists of EPR and magnet ometry measurements. The Mn-P4 LB film undergoes a transition to a long-ran ge, canted antiferromagnetic state below 14.8 +/- 0.2 K and is only the sec ond example of a continuous lattice LB film to exhibit spontaneous magnetiz ation. These results demonstrate that it is possible to prepare metal phosp honate LB films of functionalized organophosphonic acids while retaining bo th the inorganic continuous lattice structure and magnetic exchange pathway s of the known solid-state metal organophosphonates. (C) 1999 Academic Pres s.