A magnetic study of the one dimensional Sr<InlineEquation ID="Equ1"> <EquationSource Format="TEX">$\mathsf{_{3}}$</EquationSource> </InlineEquation>NiIrO<InlineEquation ID="Equ2"> <EquationSource Format="TEX">$\mathsf{_{6}}$</EquationSource> </InlineEquation> compound

The magnetic properties of a polycrystalline Sr<Subscript>3</Subscript>NiIrO<Subscript>6</Subscript> sample have been investigated by means of susceptibility and magnetization measurements. On the one hand, it is found that this compound, made of magnetic chains on a triangular lattice, behaves very similarly to Ca<Subscript>3</Subscript>CoRhO<Subscript>6</Subscript> and Ca<Subscript>3</Subscript>CoIrO<Subscript>6</Subscript>. In particular, at low temperature ( T > T <Subscript>2</Subscript> (=21 K)), a frozen state, characterized by a very slow spin dynamic, is evidenced. On the other hand, for T <Subscript>2</Subscript> > T > T <Subscript>1</Subscript> (=70 K), this phase exhibits magnetization values, smaller than the expected ones, with a 1/3 plateau reminiscent of the ferrimagnetic state of Ising spins on a triangular lattice. Nonetheless, the absence of saturation in 35 T and the low magnetization values are consistent with an antiferromagnetic intrachain coupling between Ir<Superscript>4+</Superscript> (S=1/2) and Ni<Superscript>2+</Superscript> (S=1). Sr<Subscript>3</Subscript>NiIrO<Subscript>6</Subscript> can be viewed as made of antiferromagnetically coupled ferrimagnetic chains on a triangular lattice. On the basis of these results, a magnetic (H, T) phase diagram is proposed. Copyright Springer-Verlag Berlin/Heidelberg 2003