ИСТИНА

In this work we report a new single-ion magnet representing isolated DyO+ ions dispersed in a stable inorganic diamagnetic matrix of alkaline-earth phosphates with apatite structure. Calcium and strontium hydroxyapatites with a partial substitution of metal cation for dysprosium were synthesized by a solid state reaction. Dysprosium is coordinated by 7 oxygen atoms in such compounds but with one substantially shorter Dy-O distance so forming nearly linear ion DyO+. Such well separated from each other paramagnetic ions are dispersed in a diamagnetic phosphate matrix and demonstrate a slow relaxation of magnetization as a typical single ion magnets with a very high magnetization reversal barrier up to 1043 cm-1 for the most prominent sample. Magnetic hysteresis at 1.8 K for both calcium and strontium series were searched and blocking temperature 11 K for the strontium and 4.5 K for the calcium samples were registered. Relaxation time versus temperature dependencies coincide for the samples with different dysprosium concentration for the calcium as well as the strontium range but the strontium samples are characterized by a longer relaxation times and higher magnetization reversal barrier Ueff.