Magnetic Properties of Zr $_{9}$ Ni $_{11}$ Intermetallic Compound

We report on a very interesting magnetic behavior in the intermetallic compound Zr₉N₁₁, namely, (i) spin-glass behavior and (ii) fluctuations in the magnetization versus temperature curves. The magnetic properties are consistent with structural results obtained by neutron diffraction and by scanning and transmission electron microscopies. The fluctuations are believed to arise from the Dzyaloshinskii-Moriya interactions occurring in the Zr₉N₁₁ compound. Between 7.86 kA/m and 31.85 kA/m, the temperature (Tp) of the zero-field cooled (Mzfc ) peak shifted to lower temperatures with increasing field. Tp is found to be proportional to H^b, where H is the applied field and the exponent b < 1. The value of b is found to be 0.68, which is close to the de Almeida-Thouless 2/3 power law that applies to spin glasses. Published neutron diffraction data showed that a Zr₉N₁₁ compound possessed Zr₉Pt₁₁-type tetragonal structure with columnar atomic chains parallel to the c axis and consisting of alternating Zr and Ni atoms. Small fluctuations present in the Mfc versus T plot at 31.85 kA/m are believed to be the result of atomic displacements along these chains over short distances. Another interesting featured observed in the Zr₉N₁₁ compound is the fact that at 3.98 kA/m the Mzfc values reside mostly above the corresponding Mfc values.