Ferromagnetic Cu and ferrimagnetic Co layered hydroxides incorporating cinnamate derivative layers

A series of organic-inorganic hybrid materials TM(Xcin)(OH) were synthesized and their structural and magnetic properties were investigated to discuss their magneto-structural relations, where TM = Cu, Co and Xcin = cinnamic acid (1 for TM = Cu, 8 for TM = Co), 4-methylcinnamic acid (2 for TM = Cu, 9 for TM = Co), 4-chlorocinnamic acid (3 for TM = Cu, 10 for TM = Co), trans- p-coumaric acid (4 for TM = Cu), 4-(trifluoromethyl)cinnamic acid (5 for TM = Cu), 3-phenylpropionic acid (6 for TM = Cu), trans-styrylacetic acid (7 for TM = Cu) and 1,4-Phenylenediacrylic acid (11 for TM = Co). The compounds 1-11 possess organic-inorganic multi-layered structures, in which Xcin monocarboxylate bilayers (dicarboxylate monolayers for 11) alternate TM(OH) _x inorganic monolayers. The Cu compounds1-7 exhibit soft ferromagnetic long-range-orderings below the Curie temperatures ranging from 10.8 to 14.7 K. In contrast, the Co compounds 8-11 exhibit ferrimagnetic long-range orderings with a large coercive field ( H_c = 38 kOe for 8) below the Curie temperatures ranging from 44.0 to 57.0 K. We found that the T _C values of 1-7 and 8-11 exist in a narrow temperature range although the inter-layer spacings were distributed in a wide range from 13.3 to 22.5 Å.