and I. Císa°ová

We report on the basic physical properties of a novel CeCo0.715Si2.285 compound, mainly its rich magnetic phase diagram. The compound crystallizes in the I-4m2 space group structure with extremely elongated unit cell (a = 4.12 Å, c = 32.84 Å). In a zero magnetic field it orders antiferromagnetically at TN = 10.5 K with another order-to-order transition at 9.5 K. Under application of a magnetic field along the c-axis it manifests numerous magnetic transitions in small fields (B < 500 mT), resembling the so-called devil's staircase systems. Above 1 T the magnetization is almost constant up to 14 T (maximum magnetic field applied within our study) but considerably reduced (0.3 µB/Ce) with respect to the free Ce 3+ ion. After removing the applied field, however, the high field state remains unchanged to be removed in negative fields. The compound also exhibits strong hysteresis of magnetization with respect to varying temperature or magnetic field. For fields applied along the a-axis typical behavior for the hard axis in the material with uniaxial anisotropy is observed