Quenching of spin fluctuations in the 3d and 4f aluminides YFe2Al10 and YbFe2Al10: a comparative 27Al NMR and specific heat study
Quenching of spin fluctuations in the 3d and 4f aluminides YFe2Al10 and YbFe2Al10: a comparative 27Al NMR and specific heat study
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3d 和 4f 铝化物 YFe2Al10 和 YbFe2Al10 中自旋波动的淬灭：比较 27Al NMR 和比热研究
DOI：
10.1002/pssb.201200758
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
M. Baenitz
中科院分区：
文献类型：
--
作者：
P. Khuntia;A.M. Strydom;F. Steglich;M. Baenitz
研究了两种同构铁铝化物YFe2Al10和YbFe2Al10的磁化率χ(T)、比热系数γ(T) =C(T)/T和自旋晶格驰豫速率。在10 K以下，两个体系的χ(T)、γ(T)和SLR系数 =27(1/T1T)随温度的降低呈现单调的场依赖性增加。这些分歧与量子临界点(QCP)附近的自旋涨落有关。QCP很可能是铁磁(FM)性质的，但到目前为止，在两个系统中都没有观察到低至0.35 K的磁序。施加几特斯拉的适中磁场抑制了这些性质的低对角翻转。零场和高场测量之间的比较允许确定χ(T)、γ(T)和自旋晶格弛豫系数(SLRC)27R(T)中的增强因子。令人惊讶的是，对于这两个系统，γ(T)和Thet依赖[∝ln(1/T)]的相对增强非常相似。在SLRC中，Yb-系统的增强较大，但两者都在→ 0时表现出ln(1/T)行为。因为YbFe2Al10中的Yb离子在低温下处于中价态，对观测到的自旋涨落贡献很小，所以发散非常相似。这强烈地表明了两个系统相同的基本物理和相同的能量标度。我们认为来自弱巡游Fe的占主导地位的q= 0低能FM自旋涨落是观测到的对数发散的根源。
We present investigations on the magnetic susceptibilityχ(T), the specific heat coefficientγ(T) =C(T)/T, and the spin‐lattice relaxation (SLR) rate on the two isostructural iron aluminides YFe2Al10and YbFe2Al10. Below 10 K, both systems display a monotonous field‐dependent increase with decreasing temperature inχ(T),γ(T) and the SLR coefficient27R(T) =27(1/T1T). These divergences are associated with spin fluctuations near a quantum critical point (QCP). Most probably, the QCP is of ferromagnetic (FM) nature, but so far no magnetic order is observed in either system down to 0.35 K. The application of moderate fields of a few Tesla suppresses the low‐Tupturn in the properties. The comparison between zero‐field and high field measurements allow for the determination of enhancement factors inχ(T), theγ(T), and the spin‐lattice relaxation coefficient (SLRC)27R(T). Surprisingly, the relative enhancement inγ(T) and theT‐dependence [∝ ln(1/T)] are very similar for both systems. In the SLRC, the enhancement is larger for the Yb‐system but both show ln(1/T) behavior forT→ 0. The divergences are very similar because the Yb ions in YbFe2Al10are in an intermediate valence state at low temperatures and contribute only very little towards the observed spin fluctuations. This indicates strongly the same underlying physics and the same energy scales for both systems. We propose the presence of dominantq= 0 low‐energy FM spin fluctuations from weak itinerant Fe as the origin for the observed logarithmic divergences.
影响因子：
3.7
作者：
P. Khuntia;A. Strydom;L. S. Wu;M. Aronson;Frank Steglich;M. Baenitz
通讯作者：
P. Khuntia;A. Strydom;L. S. Wu;M. Aronson;Frank Steglich;M. Baenitz
混合价化合物CeFe2 Al10的27 l NMR研究
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
Sz;C. Lue
通讯作者：
C. Lue