Structural, magnetic, and Mössbauer spectral study of the icosahedral quasicrystalZn77Fe7Sc16

Abstract

The structural, magnetic, and M\"ossbauer spectral properties of the icosahedral quasicrystal ${\text{Zn}}_{77}{\text{Fe}}_{7}{\text{Sc}}_{16}$ are reported. The thermodynamically stable quasicrystal ${\text{Zn}}_{77}{\text{Fe}}_{7}{\text{Sc}}_{16}$ has a primitive six-dimensional Bravais lattice at room temperature with a six-dimensional hypercubic lattice constant of $7.087(1)\text{ }\text{\AA{}}$. Based on dc magnetization measurements, no evidence is found for a transition to a ground state with long-range magnetic order in the temperature range between 2 and 300 K. The dc zero-field-cooled and field-cooled susceptibility data indicate that the studied quasicrystal is a spin glass with freezing temperature ${T}_{f}=7.75(2)\text{ }\text{K}$. This is further confirmed by observing aging effects through the dc zero-field-cooled magnetization and the thermoremanent magnetization time decays and by the analysis of the frequency dependence of ${T}_{f}$ using the Vogel-Fulcher law and the dynamic scaling behavior near ${T}_{f}$. However, the observed increase in the thermoremanent magnetization with the magnetic field in the low-field regime is incompatible with the ultrametrically organized phase space of a canonical spin glass. The nature of the spin-glass state of the icosahedral quasicrystal ${\text{Zn}}_{77}{\text{Fe}}_{7}{\text{Sc}}_{16}$ is therefore fundamentally different from that of a canonical spin glass. The bimodal distribution of the electric quadrupole splitting and of the hyperfine magnetic field derived from M\"ossbauer spectra indicates the existence of two classes of Fe sites.