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Electrical Resistivity near the Magnetic Transition of Some Rare-Earth Laves Phase Compounds

1970; American Physical Society; Volume: 2; Issue: 3 Linguagem: Inglês

10.1103/physrevb.2.665

0556-2805

M. P. Kawatra, J. A. Mydosh, J. I. Budnick,

Magnetic properties of thin films

From the measured temperature dependence of the electrical resistivity $\ensuremath{\rho}(T)$, we have computed the temperature derivative $\frac{d\ensuremath{\rho}}{\mathrm{dT}}$ with particular emphasis on its behavior in the critical region for six ferromagnetic rare-earth cubic Laves phase compounds: Gd${\mathrm{Al}}_{2}$, Gd${\mathrm{Co}}_{2}$, Gd${\mathrm{Ni}}_{2}$, Gd${\mathrm{Pt}}_{2}$, Gd${\mathrm{Rh}}_{2}$, and Dy${\mathrm{Al}}_{2}$. All samples are characterized by pronounced changes in $\frac{d\ensuremath{\rho}}{\mathrm{dT}}$ in the vicinity of the magnetic ordering temperature ${T}_{c}$. In Gd${\mathrm{Ni}}_{2}$, Gd${\mathrm{Pt}}_{2}$, and Gd${\mathrm{Rh}}_{2}$, as the temperature is decreased toward ${T}_{c}$, a minimum in $\frac{d\ensuremath{\rho}}{\mathrm{dT}}$, followed by a maximum, is observed. This behavior is consistent with that predicted from the long-range nature of the short-range spin fluctuations in the framework of the molecular field theory. The behavior of $\frac{d\ensuremath{\rho}}{\mathrm{dT}}$ for Gd${\mathrm{Al}}_{2}$ and Dy${\mathrm{Al}}_{2}$ shows only a broad maximum, whereas for Gd${\mathrm{Co}}_{2}$, $\frac{d\ensuremath{\rho}}{\mathrm{dT}}$ has a sharp peak at about ${T}_{c}$ --- very similar to that found in transition metals.