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arXiv 0705.1072cond-mat.str-elcond-mat.mtrl-sci
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(反)铁磁材料射频磁化率的精确测量

Precise measurements of radio-frequency magnetic susceptibility in (anti)ferromagnetic materials

M. D. Vannette, A. Safa-Sefat, S. Jia, S. A. Law, G. Lapertot, S. L. Bud'ko, P. C. Canfield, J. Schmalian, R. Prozorov

摘要:

研究了几种具有铁磁、反铁磁和变磁相变的金属间化合物材料的动态磁化率$χ$。通过使用14 MHz隧道二极管振荡器(TDO)进行精确测量,可以详细了解$χ$的场和温度依赖性。特别地,局部磁矩铁磁体在居里温度$T_c$附近显示出$χ(T)$的尖峰。峰值幅度降低,并转移到更高的温度与非常小的直流电场。CeVSb $_3$的各向异性测量表明,如果磁易轴与激发场对齐,则存在该峰。与此形成鲜明对比的是,小力矩,巡回铁磁体(即,ZrZn $_2$)在$χ(T)$中显示出宽的最大值,其对施加的场有不同的响应。我们认为,TDO测量提供了一个非常敏感的方式来区分本地和巡回时刻磁订单。局域磁矩反铁磁体在Néel温度$T_N$处不显示峰值,但在低于$T_N$时,由于自旋无序散射的损失改变了交流激发场的穿透深度,$χ$仅急剧减小。此外,我们表明,TDO是能够检测自旋顺序的变化,以及变磁过渡。最后,在CeVSb $_3$和CeAgSb $_2$中讨论了$T_C$附近的$χ(T,H)$的临界标度。

英文摘要:

Dynamic magnetic susceptibility, $χ$, was studied in several intermetallic materials exhibiting ferromagnetic, antiferromagnetic and metamagnetic transitions. Precise measurements by using a 14 MHz tunnel diode oscillator (TDO) allow detailed insight into the field and temperature dependence of $χ$. In particular, local moment ferromagnets show a sharp peak in $χ(T)$ near the Curie temperature, $T_c$. The peak amplitude decreases and shifts to higher temperatures with very small applied dc fields. Anisotropic measurements of CeVSb$_3$ show that this peak is present provided the magnetic easy axis is aligned with the excitation field. In a striking contrast, small moment, itinerant ferromagnets (i.e., ZrZn$_2$) show a broad maximum in $χ(T)$ that responds differently to applied field. We believe that TDO measurements provide a very sensitive way to distinguish between local and itinerant moment magnetic orders. Local moment antiferromagnets do not show a peak at the Néel temperature, $T_N$, but only a sharp decrease of $χ$ below $T_N$ due to the loss of spin-disorder scattering changing the penetration depth of the ac excitation field. Furthermore, we show that the TDO is capable of detecting changes in spin order as well as metamagnetic transitions. Finally, critical scaling of $χ(T,H)$ in the vicinity of $T_C$ is discussed in CeVSb$_3$ and CeAgSb$_2$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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