Evolution of short-range magnetic correlations in ferromagnetic Ni-V alloys
Evolution of short-range magnetic correlations in ferromagnetic Ni-V alloys
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DOI：
10.1103/physrevb.107.054409
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发表时间：
2022-07
影响因子：
3.7
通讯作者：
S. Bhattarai;H. Adawi;J. Lussier;A. Gebretsadik;M. Dzero;K. Krycka;A. Schroeder
中科院分区：
文献类型：
--
作者：
S. Bhattarai;H. Adawi;J. Lussier;A. Gebretsadik;M. Dzero;K. Krycka;A. Schroeder
实验研究了具有小角中子散射(SANS)的二元合金在铁磁量子临界点附近的磁关联是如何发展的。当巡回铁磁镍与钒合金化时，铁磁有序被不断地抑制。当钒浓度达到临界值Xc=0.116时，临界温度T_c为零，表明存在一个分离铁磁和顺磁相的量子临界点。早期的磁化强度和核磁共振数据表明，在Ni(1-x)V(X)中存在磁性不均匀，特别是识别出靠近XC的、顺磁的和具有非平凡动力学性质的铁磁一侧的磁团簇[R.Wang等人，Phys.莱特牧师。118、267202(2017年)]。我们给出了用全极化分析对x=0.10和x=0.11的多晶Ni(1-x)V(X)样品进行SANS研究的结果，其中x=0.10和x=0.11的样品的低临界温度T_c低于50K。对于这两个接近X_c的Ni-V样品，我们发现在低温下存在纳米尺度的各向同性磁短程关联。它们在较高的磁场中逐渐被抑制。此外，在T_c以下还出现了长程有序磁畴的特征。嵌入到铁磁有序相中的这些磁性团簇的比例向XC方向生长，并与从磁化强度和$mU$SR数据估计的团簇比例一致。我们的SANS研究为接近量子临界点的铁磁合金中不均匀的本质提供了新的见解。
We experimentally study how the magnetic correlations develop in a binary alloy close to the ferromagnetic quantum critical point with small-angle neutron scattering (SANS). Upon alloying the itinerant ferromagnet nickel with vanadium, the ferromagnetic order is continuously suppressed. The critical temperature Tc vanishes when vanadium concentrations reach the critical value of xc=0.116 indicating a quantum critical point separating the ferromagnetic and paramagnetic phases. Earlier magnetization and $\mu$SR data have indicated the presence of magnetic inhomogeneities in Ni(1-x)V(x) and, in particular, recognize the magnetic clusters close to xc, on the paramagnetic and on the ferromagnetic sides with nontrivial dynamical properties [R. Wang et al., Phys. Rev. Lett. 118, 267202 (2017)]. We present the results of SANS study with full polarization analysis of polycrystalline Ni(1-x)V(x) samples with x=0.10 and x=0.11 with low critical temperatures Tc below 50 K. For both Ni-V samples close to xc we find isotropic magnetic short-range correlations in the nanometer-scale persisting at low temperatures. They are suppressed gradually in higher magnetic fields. In addition, signatures of long-range ordered magnetic domains are present below Tc. The fraction of these magnetic clusters embedded in the ferromagnetic ordered phase grows towards xc and agrees well with the cluster fraction estimate from the magnetization and $\mu$SR data. Our SANS studies provide new insights into the nature of the inhomogeneities in a ferromagnetic alloy close to a quantum critical point.