Zero-field and magnetic-field low-temperature heat capacity of solid-state electrotransport-purified erbium.
Zero-field and magnetic-field low-temperature heat capacity of solid-state electrotransport-purified erbium.
复制标题
固态电传输纯化铒的零场和磁场低温热容。
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
D. Fort
中科院分区：
文献类型：
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作者：
V. Pecharsky;K. Gschneidner;D. Fort
在99.97 at上进行了零场（1.5—80k）和高磁场（1.5—20k）低温热容测量。% （99.996 wt %）纯多晶铒。电子比热系数（零场）为8.7ifmmodepmelse extpmfi{}0.1 mJ/mol ${mathm {K}}^{2}$，德拜温度为176.9ifmmodepmelse extpmfi{}0.4 K。在19k附近，铒的“铁磁”跃迁表现出极大而尖锐的热容最大值（169 J/mol K），在25.1、27.5、42、48.9和51.4 K处观察到另外5个热容异常。51.4 k峰与基面上的反铁磁有序有关，其他4个异常与两种不同的相称反铁磁结构之间的自旋滑移跃迁有关。外加磁场使铁磁热容峰值向高温方向移动，极大值被显著抑制和展宽，并使总热容在温度降至5 K左右时低于磁有序最大值。在较低温度下，高磁场（hg5t）增加了样品的热容，这是由于$^{167}数学{Er}$超精细耦合和电子贡献的增加。原子核处的有效磁场从H=0时的7.2 MOe增加到H=9.85 T时的10.3 MOe，电子比常数（费米能级的态密度）在Hensuremath{sim}2 T时由于基面矩的自旋取向而增加了15%。这种变化在磁对热容的贡献上也很明显。
Zero-field (1.5--80 K) and high-magnetic-field (1.5--20 K) low-temperature heat-capacity measurements have been carried out on 99.97 at. % (99.996 wt %) pure polycrystalline erbium. The electronic specific-heat coefficient (in zero field) was found to be 8.7ifmmodepmelse extpmfi{}0.1 mJ/mol ${mathrm{K}}^{2}$ and the Debye temperature to be 176.9ifmmodepmelse extpmfi{}0.4 K. The ``ferromagnetic' transition of erbium around 19 K exhibits a tremendously large and sharp heat-capacity maximum of 169 J/mol K. Five other heat-capacity anomalies at 25.1, 27.5, 42, 48.9, and 51.4 K were observed. The 51.4-K peak is associated with antiferromagnetic ordering in the basal plane, and the other four anomalies are associated with spin-slip transitions between two different commensurate antiferromagnetic structures. An external magnetic field shifts the ferromagnetic heat-capacity peak toward higher temperatures with a remarkable suppression and broadening of the maximum, and reduces the total heat capacity below the magnetic ordering maximum for temperatures down to about 5 K. At lower temperatures, the high-magnetic field (Hg5 T) increases the sample heat capacity due to an increase in both the $^{167}mathrm{Er}$ hyperfine coupling and electronic contributions. The effective magnetic field at the nucleus increases from 7.2 MOe at H=0 to 10.3 MOe at H=9.85 T. The electronic specific constant (density of state at the Fermi level) exhibits a 15% increase at Hensuremath{sim}2 T due to a spin reorientation of the basal plane moments. This change is also evident in the magnetic contribution to the heat capacity.