Non-Fermi liquid behavior and signature of Griffiths phase in Ni–Cr binary alloy
08 Apr 2021-Journal of Applied Physics (AIP Publishing LLCAIP Publishing)-Vol. 129, Iss: 14, pp 143901
TL;DR: In this article, the effect of Cr on magnetic, electrical, and thermal properties of Ni100−xCrx binary alloys has been investigated, and the results show that with the increase in Cr concentration, magnetic moment and Curie temperature linearly decreased and the ferromagnetic order was suppressed at the critical concentration.
Abstract: Detailed magnetic, electrical, and thermal property measurements have been carried out on Ni100−xCrx binary alloys, mainly to study the effect of Cr. The following points emerge from this study: with the increase in Cr concentration, magnetic moment and Curie temperature linearly decreased and the ferromagnetic order is completely suppressed at the critical concentration (xcr ≈ 12.16 ± 0.03). The Rhodes–Wohlfarth ratio increases as the concentration approaches xcr, suggesting a weak itinerant ferromagnetic character of NiCr compositions (x < xcr). Analysis of low-temperature electrical resistivity and specific heat data suggests that the spin fluctuation’s contribution increases and the Fermi-liquid behavior breaks down as the concentration approaches xcr. For x ∼ xcr, the dc susceptibility χ(T) deviates from the Curie–Weiss law reminiscent to that of the Griffiths phase. The low-temperature magnetic isotherms of Ni–Cr follow power law, M ( H ) = M 0 + d λ H λ, and the non-universal exponent (λ) shows a minimum at xcr ∼ 12. Further, temperature dependence of magnetization studies also support the presence of the quantum Griffiths phase, similar to that reported in the Ni–V alloy system. The temperature dependencies of the electrical resistivity, magnetization, and specific heat follow the theoretical predictions of a quantum critical point within experimental uncertainties.
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TL;DR: In this article, the authors used the National Science Foundation (NSF) under grant numbers NSF DMR-09-29966, DMR09-01907, D MR-1401410, and D MMR-1401449, and by the Deutsche Forschungsgemeinschaft under grant number FOR-960.
Abstract: This work has been supported by the National Science Foundation under grant numbers NSF DMR-09-29966, DMR-09-01907, DMR-1401410, and DMR-1401449, and by the Deutsche Forschungsgemeinschaft under grant number FOR-960. Part of this work has been supported by the National Science Foundation under Grant. No. PHYS-1066293 and the hospitality of the Aspen Center for Physics.
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TL;DR: These experiments establish a common relationship among hidden magnetism, quantum criticality and unconventional superconductivity in copper oxides and heavy-electron systems such as CeRhIn5.
Abstract: With only a few exceptions that are well understood, conventional superconductivity does not coexist with long-range magnetic order (for example, ref. 1). Unconventional superconductivity, on the other hand, develops near a phase boundary separating magnetically ordered and magnetically disordered phases. A maximum in the superconducting transition temperature Tc develops where this boundary extrapolates to zero Kelvin, suggesting that fluctuations associated with this magnetic quantum-critical point are essential for unconventional superconductivity. Invariably, though, unconventional superconductivity masks the magnetic phase boundary when T < Tc, preventing proof of a magnetic quantum-critical point. Here we report specific-heat measurements of the pressure-tuned unconventional superconductor CeRhIn5 in which we find a line of quantum–phase transitions induced inside the superconducting state by an applied magnetic field. This quantum-critical line separates a phase of coexisting antiferromagnetism and superconductivity from a purely unconventional superconducting phase, and terminates at a quantum tetracritical point where the magnetic field completely suppresses superconductivity. The T → 0 K magnetic field–pressure phase diagram of CeRhIn5 is well described with a theoretical model developed to explain field-induced magnetism in the high-Tc copper oxides, but in which a clear delineation of quantum–phase boundaries has not been possible. These experiments establish a common relationship among hidden magnetism, quantum criticality and unconventional superconductivity in copper oxides and heavy-electron systems such as CeRhIn5.
34 citations
TL;DR: In this article , magnetic and thermal properties of Cu substituted Ni92−xCuxCr8 polycrystalline alloys close to their critical concentration (xc ~18%), where ferromagnetic order disappears.
1 citations
TL;DR: In this article , low temperature magnetic properties of Ni 92−x Al x Cr 8 alloys have been investigated and it is found that the Curie temperature and spontaneous magnetization (M SP) get suppressed around xC ≈ 7.
Abstract: In the present work we report low temperature magnetic properties of Ni 92−x Al x Cr 8 alloys. It is found that the Curie temperature and spontaneous magnetization ( M SP) get suppressed around xC ≈ 7. From the analysis of the temperature and field dependent magnetization data we have obtained high value of Rhodes–Wohlfarth ratio, which indicates the weak itinerant ferromagnetic behavior for samples below x C. This is further supported by analysing the temperature variation of M SP in the framework of spin fluctuations, SCR theory. Furthermore, the Ginzburg-Landau formalism-based on spin fluctuation theory revealed that the contribution of spin fluctuations at low temperature increases as we approach x C.
1 citations
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