Ferromagnetic properties ofZrZn2

Abstract

The low Curie temperature $({T}_{C}\ensuremath{\approx}28\phantom{\rule{0.3em}{0ex}}\mathrm{K})$ and small ordered moment $({M}_{0}\ensuremath{\approx}0.17\phantom{\rule{0.3em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}\phantom{\rule{0.3em}{0ex}}{\mathrm{f.u.}}^{\ensuremath{-}1})$ of $\mathrm{Zr}{\mathrm{Zn}}_{2}$ make it one of the few examples of a weak itinerant ferromagnet. We report the results of susceptibility, magnetization, resistivity, and specific heat measurements made on high-quality single crystals of $\mathrm{Zr}{\mathrm{Zn}}_{2}$. From magnetization scaling in the vicinity of ${T}_{C}$ $(0.001<\ensuremath{\mid}T\ensuremath{-}{T}_{C}\ensuremath{\mid}∕{T}_{C}<0.08)$, we obtain the critical exponents $\ensuremath{\beta}=0.52\ifmmode\pm\else\textpm\fi{}0.05$ and $\ensuremath{\delta}=3.20\ifmmode\pm\else\textpm\fi{}0.08$, and ${T}_{C}=27.50\ifmmode\pm\else\textpm\fi{}0.05\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Low-temperature magnetization measurements show that the easy axis is [111]. Resistivity measurements reveal an anomaly at ${T}_{C}$ and a non-Fermi liquid temperature dependence $\ensuremath{\rho}(T)={\ensuremath{\rho}}_{0}+A{T}^{n}$, where $n=1.67\ifmmode\pm\else\textpm\fi{}0.02$, for $1<T<14\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The specific heat measurements show a mean-field-like anomaly at ${T}_{C}$. We compare our results to various theoretical models.