Three-dimensional Ising ferrimagnetism of Cr-Fe-Cr trimers in FeCr2Te4

Abstract

We carried out a comprehensive study of magnetic critical behavior in single crystals of ternary chalcogenide $\mathrm{Fe}{\mathrm{Cr}}_{2}{\mathrm{Te}}_{4}$ that undergoes a ferrimagnetic transition below ${T}_{c}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}$ 123 K. Detailed critical behavior analysis and scaled magnetic entropy change indicate a second-order ferrimagnetic transition. Critical exponents $\ensuremath{\beta}=0.30(1)$ with ${T}_{c}=122.4(5)\phantom{\rule{0.16em}{0ex}}\mathrm{K}, \ensuremath{\gamma}=1.22(1)$ with ${T}_{c}=122.8(1)\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and $\ensuremath{\delta}=4.24(2)$ at ${T}_{c}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}123\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ suggest that the spins approach the three-dimensional Ising ($\ensuremath{\beta}=0.325, \ensuremath{\gamma}=1.24$, and $\ensuremath{\delta}=4.82$) model coupled with attractive long-range interactions between spins that decay as $J(r)\ensuremath{\approx}{r}^{\ensuremath{-}4.88}$. Our results suggest that the ferrimagnetism in $\mathrm{Fe}{\mathrm{Cr}}_{2}{\mathrm{Te}}_{4}$ is due to itinerant ferromagnetism among the antiferromagnetically coupled Cr-Fe-Cr trimers.