Ferromagnetism in 5f-band metamagnet UCoAl induced by Os doping

Андреев, А.В.; Shirasaki, Kenji; Šebek, J.; Vejpravová, J.; Gorbunov, D. I.; Havela, L.; Daniš, S.; Yamamura, Tomoo

doi:10.1016/j.jallcom.2016.04.226

Cited by 12 publications

(7 citation statements)

References 40 publications

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“…3 (a) and (b), respectively. γ ∼ 59 mJ/K 2 mol for U(Co 0.980 Os 0.020 )Al well agrees with the value previously estimated from a higher temperature data [8]. As shown in Fig.…”

Section: Resultssupporting

confidence: 91%

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Maeda

Kimura

Kabeya

et al. 2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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Low temperature specific heat of U(Co 1−x Os x)Al is investigated. Anomalous temperature dependences are observed for UCoAl and U(Co 0.998 Os 0.002)Al, whose ground state locates near the quantum phase transition of the itinerant-electron ferromagnetism. This suggests that an additional contribution to the electronic specific heat exists in these samples. The effect of conventional spin fluctuations cannot explain this behavior.

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“…3 (a) and (b), respectively. γ ∼ 59 mJ/K 2 mol for U(Co 0.980 Os 0.020 )Al well agrees with the value previously estimated from a higher temperature data [8]. As shown in Fig.…”

Section: Resultssupporting

confidence: 91%

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Maeda

Kimura

Kabeya

et al. 2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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“…Table I shows the critical exponents β, γ ′ , γ, and δ in UTeS and USeS, and those in mean field theory and various theoretical models with SR exchange interactions of a form J(r) ∼ e −r/b [17,22,23]. The exponents in the uranium ferromagnetic superconductors UGe 2 and URhGe [16], and some uranium ferromagnets URhSi [24], UIr [25,26], and U(Co 0.98 Os 0.02 )Al [27,28] are also shown. The sets of the exponents in UTeS and USeS are similar to those of the uranium ferromagnets.…”

Section: Discussionmentioning

confidence: 99%

Novel universality class for the ferromagnetic transition in the low carrier concentration systems UTeS and USeS exhibiting large negative magnetoresistance

et al. 2019

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We report the novel critical behavior of magnetization in low carrier concentration systems UTeS and USeS that exhibit the large negative magnetoresistance around the ferromagnetic transition temperatures TC ∼ 85 and 23 K, respectively. UTeS and USeS crystallize in the same orthorhombic TiNiSi-type crystal structure as those of uranium ferromagnetic superconductors URhGe and UCoGe. We determine the critical exponents, β for the spontaneous magnetization Ms, γ for the magnetic susceptibility χ, and δ for the magnetization isotherm at TC with several methods. The ferromagnetic states in UTeS and USeS have strong uniaxial magnetic anisotropy. However, the critical exponents in the two compounds are different from those in the three-dimensional Ising model with short-range magnetic exchange interactions. Similar sets of the critical exponents have been reported for the uranium ferromagnetic superconductors UGe2 and URhGe, and uranium intermetallic ferromagnets URhSi, UIr and U(Co0.98Os0.02)Al. The universality class of the ferromagnetic transitions in UTeS and USeS may belong to the same one for the uranium compounds. The novel critical phenomenon associated with the ferromagnetic transition is observed not only in the uranium intermetallic ferromagnets with the itinerant 5f electrons but also in the low carrier concentration systems UTeS and USeS with the localized 5f electrons. The large negative magnetoresistance in UTeS and USeS, and the superconductivity in UGe2 and URhGe share the similarity of their closeness to the ferromagnetism characterized by the novel critical exponents.PACS numbers:

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“…Single crystals of UCo 1-x Os x Al were grown in the tri-arc or tetra-arc furnace using the Czochralski method. The lattice constants were determined by powder X-ray diffraction using crystals prepared from the pulled ingot [6]. The elastic modulus C 44 was measured by using the phase comparison type pulse echo method and is expressed by the equation C = v 2 , where  = 10.514 g/cm 3 is the mass density and v is the sound velocity in a sample.…”

Section: Methodsmentioning

confidence: 99%

“…UCoAl is paramagnetic in the ground state, but it becomes to show ferromagnetism by a slight uniaxial pressure along the c-axis which is the magnetically easy axis or by partially replacing Co for Os. By applying the magnetic field along the c-axis, the metamagnetic phase transition from paramagnetic to ferromagnetic phase occurs at the critical magnetic field of 0.7 T [4][5][6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Low Frequency Dependent Elastic Modulus in UCo₁₋_xOs_xAl

Kumano

Ishii

Horio

et al. 2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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UCoAl with the hexagonal ZrNiAl-type structure shows an itinerant metamagnetic phase transition at 0.7 T in the magnetic field along the c-axis. Whereas, this compound becomes to undergo a ferromagnetic phase transition in zero field by substituting Os for Co. UCo 0.995 Os 0.005 Al exhibits the ferromagnetic phase transition at T C = 8 K. At high temperatures, the temperature dependence of the transverse elastic modulus C 44 in UCo 0.995 Os 0.005 Al shows a slight softening below 50 K. The softening turns to an abrupt hardening below 30 K. With further decreasing temperature, a bending is observed at T C. Although T C changes sensitively by applying the magnetic fields, the temperature of the elastic hardening is robust in the magnetic fields. This elastic hardening is not caused by a magnetic origin. We measured ultrasonic frequency dependences of C 44 and found that the temperature of the elastic hardening increases with increasing ultrasonic frequency. We propose that this ultrasonic frequency dependence is due to a large amplitude atomic motion of constituent atoms.

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Ferromagnetism in 5f-band metamagnet UCoAl induced by Os doping

Cited by 12 publications

References 40 publications

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Novel universality class for the ferromagnetic transition in the low carrier concentration systems UTeS and USeS exhibiting large negative magnetoresistance

Low Frequency Dependent Elastic Modulus in UCo₁₋_xOs_xAl

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Ferromagnetism in 5f-band metamagnet UCoAl induced by Os doping

Cited by 12 publications

References 40 publications

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Low Temperature Specific Heat of UCoAl near the Ferromagnetic Quantum Phase Transition

Novel universality class for the ferromagnetic transition in the low carrier concentration systems UTeS and USeS exhibiting large negative magnetoresistance

Low Frequency Dependent Elastic Modulus in UCo1−xOsxAl

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Low Frequency Dependent Elastic Modulus in UCo₁₋_xOs_xAl