Citation for published item:ngD uizhe nd qeretsdikD edne nd idEussisD r nd hroederD elmut nd ojtD homs nd fkerD eter tF nd rttD prnis vF nd flundellD tephen tF nd vnsterD om nd prnkeD ssel nd w¤ ollerD tohnnes F nd geD uthrine @PHIUA 9untum qri0ths phse inside the ferromgneti phse of xiIExxF9D hysil review lettersFD IIV @PTAF pF PTUPHPF Further information on publisher's website: Reprinted with permission from the American Physical Society: Physical Review Letters 118, 267202 c (2017) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

We present small angle neutron scattering (SANS) data collected on polycrystalline Ni 1−x V x samples with x ≥ 0.10 with confirmed random atomic distribution. We aim to determine the relevant length scales of magnetic correlations in ferromagnetic samples with low critical temperatures T c that show signs of magnetic inhomogeneities in magnetization and µSR data. The SANS study reveals signatures of long-range order and coexistence of short-range magnetic correlations in this randomly disordered ferromagnetic alloy. We show the advantages of a polarization analysis in identifying the main magnetic contributions from the dominating nuclear scattering.Formation of ferromagnetism in metals is still an active field for discovery of novel phases and mechanisms in condensed matter physics 1 . In particular, the control of disorder and determination of how inhomogeneities affect magnetic properties remains a significant challenge. Small angle neutron scattering (SANS) is one of the prime methods 2 to characterize magnetic material at the nanoscale. It has revealed important insight in the complex structure formation of inhomogeneous magnets with defects or internal structures from bulk alloys 3 to amorphous and nanocrystalline magnetic materials 2,4 . In this study we focus on the binary transition metal alloy Ni 1−x V x , that presents an example of a diluted inhomogeneous ferromagnet produced by random atomic distribution 5,6 . The onset of ferromagnetic order of Ni at T c = 630 K is suppressed towards zero with sufficient V concentration of x c = 0.116 7 . Previous magnetization and µSR studies show signatures of fluctuating clusters 7 from Ni-rich regions for paramagnetic samples with x > x c . These persist also into the ferromagnetic state close to x c and coexist with the static order 5 evolving below T c . With SANS we aim to measure the magnetic cluster sizes and their effect on the static order in this random disordered system. We present a SANS study with polarization analysis 8 to extract magnetic scattering that would otherwise be dominated by nuclear scattering.For this study we used the same polycrystalline samples of Ni 1−x V x that were prepared for optimal random distribution and characterized by several methods 6 from previous studies 5,7 . Several pellets of 3 mm diameter of each concentration were wrapped in Al foil and mounted on Al-sample holder framed with Cd-mask and connected to the cold plate of the cryostat. The SANS experiments were performed at GPSANS, HFIR, Oak Ridge National Lab and at NG7SANS 9 , NCNR, NIST. We show detailed data from NIST of Ni 0.90 V 0.10 samples using also polarized neutrons (tracking the polarization (p) state before and after sample). The SANS intensity was collected in the xy-plane on a 2D a) Electronic mail: aschroe2@kent.edu b) Present address: Intel, Chandler AZ, USA detector at different distances to cover a wave vector (Q)range of (0.06-1) nm −1 with neutron wavelengths of 0.55 nm and 0.75 nm. Taking advantage of supermirror polarizer and 3 He-cell as spin ana...

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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 µSR data have indicated the presence of magnetic inhomogeneities in Ni1−xVx and, in particular, recognize the magnetic clusters close to xc, on the paramagnetic and on the ferromagnetic sides with nontrivial dynamical properties. We present the results of SANS study with full polarization analysis of polycrystalline Ni1−xVx samples with x = 0.10 and x = 0.11 with low critical temperatures Tc < 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 µSR data. Our SANS studies provide new insights into the nature of the inhomogeneities in a ferromagnetic alloy close to a quantum critical point.

We present a pair distribution function (PDF) analysis from neutron diffraction data of the Ni1−xVx alloy in the Ni-rich regime. Such structural study aims to clarify the origin of the magnetic inhomogeneities associated with the quantum Griffiths phase close to the ferromagneticparamagnetic quantum phase transition. The PDF analysis successfully reveals the details of the structure and chemical distribution of our Ni1−xVx polycrystalline samples prepared with hightemperature annealing and rapid cooling protocol. This study confirms the expectations that all Ni1−xVx samples with 0 ≤ x ≤ 0.15 crystallize in a single phase fcc structure with some residual strain. The increase of the lattice constant and the atomic displacement parameter with Vconcentration x is consistently explained by a random occupation of V and Ni-atoms on the lattice, with a radius ratio (rV/rNi) of 1.05. Probing alternate, simple models of the local PDF, such as V-clusters or ordered structures (Ni8V, Ni3V) give inferior results compared to a random occupation. This investigation strongly supports that the magnetic clusters in the binary alloy Ni1−xVx originate from Ni-rich regions created from random occupation rather than from chemical clusters. It reveals that Ni1−xVx is one of the rare examples of a solid solution in a wide concentration regime (up to x = 0.15) persisting down to low temperatures (T = 15 K).