ac-susceptibility anomaly and magnetic anisotropy ofR2Co17compounds, withR=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu

摘要: The temperature dependence of the ac susceptibility, \ensuremath{\chi}' and \ensuremath{\chi}'', was measured in range from 4.2 to 300 K for various polycrystalline compounds ${\mathit{R}}_{2}$${\mathrm{Co}}_{17}$, with R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu single-crystalline R=Pr, Er. A spin-reorientation transition traced ${\mathrm{Pr}}_{2}$${\mathrm{Co}}_{17}$ ${\mathrm{Nd}}_{2}$${\mathrm{Co}}_{17}$ at 180 175 K, respectively. An anomalous phenomenon, which observed ${\mathit{R}}_{2}$${\mathrm{Co}}_{17}$ compounds, R=Tb, is characterized by a peak curve \ensuremath{\chi}'' versus T. It deduced that nature this phenomenon correlated magnetic anisotropy within basal plane. This anomaly attributed temperature-induced domain-wall movement under excitation external field. For uniaxial-anisotropy ${\mathrm{Er}}_{2}$${\mathrm{Co}}_{17}$ ${\mathrm{Tm}}_{2}$${\mathrm{Co}}_{17}$, sharp change shape susceptibility observed. No \ensuremath{\chi}'(T) \ensuremath{\chi}''(T) detectable ${\mathrm{Y}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{Ce}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{Gd}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{Lu}}_{2}$${\mathrm{Co}}_{17}$. field, ${\mathit{H}}_{\mathit{A}}$, ${\mathrm{Sm}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{Er}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{Tm}}_{2}$${\mathrm{Co}}_{17}$ has been determined singular-point-detection technique 1000 K. easy-magnetization direction ${\mathrm{Ce}}_{2}$${\mathrm{Co}}_{17}$ found be along c axis over whole magnetically ordered temperature.