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Shimizu, Yasuhiro; Okai, Katsunori; Itoh, Masatoshi; Isobe, Masahiko; Yamaura, Jun‐ichi; Yamauchi, Touru; Ueda, Yutaka

doi:10.1103/physrevb.83.155111

Cited by 23 publications

(8 citation statements)

References 33 publications

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“…The anomaly in the χ m (T ) curve at T c is thus likely to show the formation of a spin-singlet-like state, as for other vanadium oxides, e.g., V 4 O 7 (Refs. [18,19]) and K 2 V 8 O 16 [20][21][22]. A slight structural change in Sr 2 VO 4 (Ref.…”

Section: Fig 3 (Color Online)mentioning

confidence: 98%

Hidden magnetic order in Sr2VO4clarified withμ+SR

et al. 2014

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In order to elucidate the magnetic ground state of Sr 2 VO 4 , we have measured muon spin rotation and relaxation (μ + SR) spectra of a powder sample in the temperature range between 1.8 and 140 K. As a result, we have clarified that the transition at 105 K is not magnetic but structural and/or electric in origin and found the appearance of static antiferromagnetic (AF) order below 8 K. Moreover, the distribution of the internal AF field was found to be very broad, even at the lowest temperature measured. These results are consistent with the formation of an orbital-stripe order with collinear AF order for the magnetic ground state of Sr 2 VO 4 .Tetragonal Sr 2 VO 4 with a K 2 NiF 4 -type structure has been considered as an analog of a parent compound of the first superconducting cuprate, i.e., La 2 CuO 4 , since the electron configuration of the V 4+ ion is t 1 2g with S = 1/2 in a tetragonal crystal field of a VO 6 octahedron [1-7]. Although susceptibility (χ m ) measurements clearly show a magnetic anomaly at 105 K (=T c ) [6], a past neutron diffraction study reported the absence of magnetic peaks even at 5 K [2]. Since x-ray diffraction studies revealed a sudden enhancement of the c/a ratio below T c [6], it was proposed that an orbital-ordering transition occurs at T c . In fact, first principles calculations predicted an antiferromagnetic (AF) and orbital-ordered state with a nontrivial and large unit cell structure in the ground state, because of the coexistence and competition of ferromagnetic and AF exchange interactions [8,9].Recently, a more exciting possibility was proposed, namely, that a hidden magnetic order is induced by spin-orbit coupling for a t 1 2g electron system [10]. Such work also predicted an unconventional magnetic octupolar ordering at low T for Sr 2 VO 4 . Furthermore, alternating spin-orbital order in the ab plane was proposed by considering the effects of spin-orbit coupling, crystal field, and superexchange on the energy levels of the V 4+ ions [11].Despite the above attractive predictions, there are few reports on Sr 2 VO 4 utilizing microscopic magnetic techniques [12]. Macroscopic magnetic measurements such as χ m and neutron scattering usually give us significant insight into the ground state of magnetically ordered solids. However, such techniques are sometimes not suitable, particularly for the materials exhibiting order with a broad field distribution, i.e., when short-range order, random, or nearly random order appears in a material, due to the absence of periodic structure and/or the presence of rapid fluctuations. In contrast, the muon spin rotation and relaxation (μ + SR) technique is very sensitive * e0589@mosk.tytlabs.co.jp to local magnetic environments with a different time window compared to neutron scattering; thus μ + SR has provided crucial information on the magnetic ground state of materials [13,14]. We have therefore performed a μ + SR experiment on Sr 2 VO 4 and found the appearance of magnetic order not below T c but below 8 K.A powder sample of Sr 2 VO 4 w...

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Section: Fig 3 (Color Online)mentioning

confidence: 98%

Hidden magnetic order in Sr2VO4clarified withμ+SR

et al. 2014

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“…(3). 18,21 In contrast, S2 has the negative K without the nuclear quadrupole splitting, indicating −K s > K orb . Namely, χ s measured by S2 is larger than that measured by S1.…”

Section: Experimental Results and Analysismentioning

confidence: 98%

“…12,13 The magnetic hyperfine interaction between d spins and a nuclear spin, which is measured by the anisotropy of the NMR frequency, have elucidated orbital orders in ferromagnets [13][14][15][16] and the orbitaldependent spin susceptibility in paramagnetic metals. 17,18 The electrostatic interaction between the asymmetric electric field gradient (EFG) and the nucleus, which is measured by the anisotropy of the nuclear quadrupole splitting frequency δν, also reflects the 3d quadrupole moment governed by the spatial charge distribution. 13,18,19 The latter interaction is useful for nonmagnetic materials without the 3d spin polarization.…”

Section: Introductionmentioning

confidence: 99%

“…17,18 The electrostatic interaction between the asymmetric electric field gradient (EFG) and the nucleus, which is measured by the anisotropy of the nuclear quadrupole splitting frequency δν, also reflects the 3d quadrupole moment governed by the spatial charge distribution. 13,18,19 The latter interaction is useful for nonmagnetic materials without the 3d spin polarization.…”

Section: Introductionmentioning

confidence: 99%

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Spin-singlet trimer state induced by competing orbital order in triangular-lattice BaV10O15

et al. 2011

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Local spin and orbital textures are investigated by 51 V NMR measurements on a triangular-lattice compound BaV 10 O 15 with orbital degrees of freedom and itinerant electrons. The Knight shift shows the spin-singlet V trimer formation in a itinerant phase above the semiconductor-insulator transition temperature T SI = 140 K. Below T SI , the observation of the asymmetric electric hyperfine coupling tensor agrees with the orbital order giving direct d-d bonds of the trimer. The remaining paramagnetic spins on a V tetramer exhibit an antiferromagnetic long-range order accompanied by a ferro-type order. The coexistence of the trimer and tetramer with the two opposite magnetism is ascribed to the orbitally induced Peierls instability on a non-half-filling triangular lattice with nonuniform V-V separation.

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“…X-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) show that the V 4+ -V 4+ pair formation is essential for both the MIT and the suppression of the magnetic susceptibility [7]. In addition, 51 V NMR measurements at ambient and high pressures support the ordering of the V 3d xy orbitals and the formation of the spin singlets along the chain [8].…”

Section: Introductionmentioning

confidence: 99%

Study of Electronic Structures in Hollandite-Type Vanadium Oxide by Means of Soft X-ray Photoelectron Spectroscopy

Higashiya

Yamasaki

Imada

et al. 2014

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013)

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The electronic structures of hollandite-type vanadium oxide K 2 V 8 O 16 , which shows the metal-insulator transition, have been investigated by means of photoelectron spectroscopy with linearly and circularly polarized soft x-rays. In the photoelectron spectra near Fermi level, the clear change of the spectral weight was seen, associated with the metal-insulator transition and the polarization of the light. We compared the experimental spectra with lineally polarized light to the results of band structure calculations based on the generalized gradient approximation with on-site Coulomb interaction. By comparison with the calculated results, it is revealed that the polarization dependence is seen in the coherent part of the spectra in both low-temperature insulating (LTI) and high-temperature metallic phases.

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Metal-insulator transition in the hollanditeK2V8O

Cited by 23 publications

References 33 publications

Hidden magnetic order in Sr2VO4clarified withμ+SR

Hidden magnetic order in Sr2VO4clarified withμ+SR

Spin-singlet trimer state induced by competing orbital order in triangular-lattice BaV10O15

Study of Electronic Structures in Hollandite-Type Vanadium Oxide by Means of Soft X-ray Photoelectron Spectroscopy

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