Ferromagnetic order in U(Rh, Co)Ge

Huy, Nguyễn Thanh; Visser, A. de

doi:10.1016/j.ssc.2009.02.013

Cited by 23 publications

(18 citation statements)

References 26 publications

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“…Our PND results support the scenario that the initial stabilization of FM in URh1-xCoxGe is realized via a growth of uranium orbital moment and the consequent localization of the 5f states on U site. This can also be generalized to other FM alloys with TiNiSi-structure such as UCo1-xFexGe 13 , URh1-xCoxGe 59 and URh1-xRuxGe 17 . Our scenario is supported by the theoretical model proposed by Silva Neto et.…”

Section: Discussionmentioning

confidence: 97%

Gradual Localization of 5fStates in Orthorhombic UTX Ferromagnets:Polarized Neutron Diffraction Study of Ru Substituted UCoGe

et al. 2015

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We report on a microscopic study of the evolution of ferromagnetism in the Ru substituted ferromagnetic superconductor (FM SC) UCoGe crystallizing in the orthorhombic TiNiSi-type structure. For that purpose, two single crystals with composition UCo0.97Ru0.03Ge and UCo0.88Ru0.12Ge have been prepared and characterized by magnetization, AC susceptibility, specific heat and electrical resistivity measurements. Both compounds have been found to order ferromagnetically below TC = 6.5 K and 7.5 K, respectively, which is considerably higher than the TC = 3 K of the parent compound UCoGe. The higher values of TC are accompanied by enhanced values of the spontaneous moment spont. = 0.11 B/f.u. and spont. = 0.21 B/f.u., respectively in comparison to the tiny spontaneous moment of UCoGe (about 0.07B/f.u.). No sign of superconductivity was detected in either compound. The magnetic moments of the samples were investigated on the microscopic scale using polarized neutron diffraction (PND) and for UCo0.88Ru0.12Ge also by soft X-ray magnetic circular dichroism (XMCD). The analysis of the PND results indicates that the observed enhancement of ferromagnetism is mainly due to the growth of the orbital part of the uranium 5f moment , reflecting a gradual localization of the 5f electrons with Ru substitution. In addition, the parallel orientation of the U and Co moments has been established in both substituted compounds. The results are discussed and compared with related isostructural ferromagnetic UTX compounds (T -transition metals, X -Si, Ge) in the context of a varying degree of the 5f-ligand hybridization.

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Section: Discussionmentioning

confidence: 97%

Gradual Localization of 5fStates in Orthorhombic UTX Ferromagnets:Polarized Neutron Diffraction Study of Ru Substituted UCoGe

et al. 2015

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“…Isostructural compounds URhGe and UCoGe, which crystallize in a TiNiSi-type structure naturally fulfill this condition, and the coexistence of ferromagnetism (FM) and SC has been discovered here 8,9) . Both FM and SC can be affected by alloying [10][11][12][13][14] , the application of a magnetic field 15,16) , and the external pressure [17][18][19] . The resulting H-T-p-x phase diagrams corroborate the close connection between FM and SC.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pressure on Magnetism of UIrGe

et al. 2017

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We report the effect of hydrostatic pressure on the electronic state of the antiferromagnet UIrGe, which is isostructural and isoelectronic with the ferromagnetic superconductors UCoGe and URhGe. A series of electrical resistivity measurements in a piston-cylinder-type cell and a cubic-anvil cell were performed at hydrostatic pressures up to 15 GPa. The Néel temperature decreases with increasing pressure. We constructed a p-T phase diagram and estimated the critical pressure pc, where the antiferromagnetism vanishes, as  12 GPa. The antiferromagnetic/paramagnetic transition appears to be first order. We suggest a scenario of competing antiferromagnetic inter-J-and ferromagnetic intra-J*-chain interactions in UIrGe. A moderate increase in the effective electron mass was detected in the vicinity of pc. A discussion of the electronic specific heat  and electron-electron correlation term A using the KadowakiWoods relation is given.

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“…For example, H R ð13.4 TÞ and T Curie ð11.8 KÞ are only slightly enhanced by Co substitution (Fig. 1), which suggests a small increase in magnetic correlations [19,20]. The spin system retains its strong Ising character along the c axis, and the magnetic susceptibility is strongly anisotropic even in the ab plain, as in pure URhGe [7] (χ c > χ b > χ a ; see the inset in Fig.…”

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confidence: 96%

“…Since both Rh and Ge nuclei have poor NMR sensitivity, we performed 59 Co NMR in URh 0.9 Co 0.1 Ge [15]. The substitution of Co for Rh is isostructural and isoelectronic, and, while it precludes superconductivity (see Supplemental Material [17]), it only minimally affects the magnetic properties [19,20]. For example, H R ð13.4 TÞ and T Curie ð11.8 KÞ are only slightly enhanced by Co substitution (Fig.…”

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confidence: 99%

Reentrant Superconductivity Driven by Quantum Tricritical Fluctuations in URhGe: Evidence fromCo59NMR inURh0.

et al. 2015

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Our measurements of the ^{59}Co NMR spin-spin relaxation in URh_{0.9}Co_{0.1}Ge reveal a divergence of electronic spin fluctuations in the vicinity of the field-induced quantum critical point at H_{R}≈13 T, around which reentrant superconductivity (RSC) occurs in the ferromagnetic heavy fermion compound URhGe. We map out the strength of spin fluctuations in the (H_{b},H_{c}) plane of magnetic field components and show that critical fluctuations develop in the same limited region near the field H_{R} as that where RSC is observed. This strongly suggests these quantum fluctuations as the pairing glue responsible for the RSC. The fluctuations observed are characteristic of a tricritical point, followed by a phase bifurcation toward quantum critical end points.

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Ferromagnetic order in U(Rh, Co)Ge

Cited by 23 publications

References 26 publications

Gradual Localization of 5fStates in Orthorhombic UTX Ferromagnets:Polarized Neutron Diffraction Study of Ru Substituted UCoGe

Gradual Localization of 5fStates in Orthorhombic UTX Ferromagnets:Polarized Neutron Diffraction Study of Ru Substituted UCoGe

Effect of Pressure on Magnetism of UIrGe

Reentrant Superconductivity Driven by Quantum Tricritical Fluctuations in URhGe: Evidence fromCo59NMR inURh0.

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