Crystal structure, magnetic, and Moessbauer studies of Cu[sub 6]Fe[sub 0. 9]V[sub 6]O[sub 19]: A compound with relaxation effect

Cu[sub 6]Fe[sub 0.9]V[sub 6]O[sub 19], grown by hydrothermal synthesis, crystallizes in the rhombohedral system, space group R3, with a = 12.9300(8)[angstrom], c = 7.1275(3)[angstrom] (T = 293 K), and Z = 3. The structure is related to that of so-called [alpha]-copper vanadate, Cu[sub 6.78]V[sub 6]O[sub 18.78]. Magnetic and Moessbauer studies were performed in order to characterize the physical properties of Cu[sub 6]Fe[sub 0.9]V[sub 6]O[sub 19]. The onset of magnetic ordering occurs close to 10 K and the iron in the trivalent state shows some relaxation effects.