Seeded Chemical Vapor Transport Growth of Cu<sub>2</sub>OSeO<sub>3</sub>

Panella, Jessica R.; Trump, Benjamin A.; Marcus, Guy; McQueen, Tyrel M.

doi:10.1021/acs.cgd.7b00879

Cited by 11 publications

(8 citation statements)

References 38 publications

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“…Phase pure, single crystals of Cu 2 OSeO 3 were grown by chemical vapor transport as described previously [23]. Specimens were cut from single-crystal ingots, oriented by x-ray diffraction, and polished into thin parallelopipeds.…”

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confidence: 99%

Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

et al. 2019

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We report studies of thermal conductivity as functions of magnetic field and temperature in the helimagnetic insulator Cu2OSeO3 that reveal novel features of the spin-phase transitions as probed by magnon heat conduction. The tilted conical spiral and low-temperature skyrmion phases, recently identified in small-angle neutron scattering studies, are clearly identified by sharp signatures in the magnon thermal conductivity. Magnon scattering associated with the presence of domain boundaries in the tilted conical phase and regions of skyrmion and conical-phase coexistence are identified.The cubic chiral magnets (MnSi, FeGe, Cu 2 OSeO 3 ) have attracted considerable attention for their complex variety of non-collinear spin phases that include spin modulations with long periods (many lattice spacings) and topological skyrmion phases. Their similar and rich magnetic phase diagrams are dictated by their common noncentrosymmetric cubic lattice symmetry and a hierarchy of competing energy scales (e.g. exchange, Dzyaloshinsky-Moriya, magnetocrystalline anisotropy, Zeeman). Recently two new spin phases, low-temperature skyrmion and "titled conical spiral," were identified in the insulating compound Cu 2 OSeO 3 by small-angle neutron scattering (SANS) [1,2]. These novel phases, arising at low temperature and relatively high magnetic field, reflect competing Zeeman and anisotropy energies that lead to surprising spin textures and a re-orientation of the long-period spin modulation direction.Here we report that field dependent thermal conductivity measurements are a particularly sensitive probe of the spin phase transitions in Cu 2 OSeO 3 because of the compound's unprecedentedly large magnon heat conductivity [3]. Rather little is known experimentally about magnons in ferro-or ferri-magnets from heat transport, their scattering or its dependency on spin textures, whether longrange ordered or not. Such information has increased in its importance and relevance with the surging interest in spintronic and magnonic device applications [4,5]. Cu 2 OSeO 3 is an ideal material for investigating these characteristics because the spin and lattice systems are weakly coupled as evidenced by very low spin-lattice damping [6,7] and by mean-free paths for both magnons and phonons as large as 0.3 mm below 2K [3]. These conditions ensure that energy (e.g. from a heater in thermal conductivity measurements) is transferred from the lattice to the spin system, but is weak enough so the contributions from phonons (κ L ) and magnons (κ m ) are approximately additive [3,8], κ ≃ κ L + κ m .Our measurements reveal a complete suppression of the magnon heat flux in the tilted conical phase along the 110 directions that we attribute to strong magnon scattering by tilt domain boundaries. This observation raises the prospect of exploiting this configuration of heat flux and applied field in a field-controllable spin-current switch. The low-temperature skyrmion phase, characterized by long-range skyrmion lattice order, supports maximum magnon heat conduct...

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Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

et al. 2019

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“…The compound can be obtained by thermal decomposition of CuSeO 3 in air at high temperatures [6] or using Cu 2 OSeO 3 . It has also been found as a contaminant during the synthesis of Cu 2 OSeO 3 [7,8]. In this work, we obtained high-quality monoclinic Cu 4 O(SeO 3 ) 3 single crystals when we tried to grow Cu 2 OSeO 3 using a CVT reaction.…”

Section: Introductionmentioning

confidence: 85%

Magnetic studies of monoclinic Cu₄O(SeO₃)₃, a copper-oxo-selenite derivative

et al. 2020

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Cu4O(SeO3)3 is a copper-oxo-selenite belonging to the CuxO(SeO3)(x–1) family of the topological chiral magnet Cu2OSeO3. We report magnetometry and specific heat data measured in a monoclinic Cu4O(SeO3)3 single crystal grown through a Chemical Vapour Transport (CVT) reaction. Our study shows a typical antiferromagnetic behaviour, with a Néel temperature TN = 58 K, similar to that of the Cu2OSeO3 and an additional transition at 13 K. The effective magnetic moment per Cu atom is 1.84 μB, close to the expected theoretical value for Cu2+. The low-temperature M(H) curves, show a transition starting at Hc1 ~ 400 Oe at 1.8 K shifting to a lower value of ~ 280 Oe at 30 K, likely from a helical into a conical intermediate phase, and a second transition at Hc2 ~ 1 kOe, above which the net moment increases linearly with applied field. The magnetisation moment value in a 90 kOe field is 0.053 μB/Cu at 1.8 K and attains a maximum value of 0.061 μB at 13 K. Low-temperature specific heat measurements confirm the presence of the magnetic transition at 13 K, slightly shifting to lower temperatures under an applied magnetic field.

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“…This paper provides a bottom-seed crystal growth process, which solves the above problems. Firstly, the vertical CVT process growth method is used, the raw materials were placed at the bottom of the quartz tube [15] . In this case, the raw material concentration at the bottom of the quartz tube will be much greater than that at the top, which is conducive to the growth of crystals at the bottom of the quartz tube when the transport distance of gas is significantly shortened.…”

Section: Introductionmentioning

confidence: 99%

Preparation of NbAs Single Crystal by the Seed Growth Process

Sun¹,

Zhao²,

Huo³

et al. 2022

Preprint

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A Weyl semimetal is a novel crystal with low-energy electronic excitations that behave as Weyl fermions. It has received worldwide interest and was believed to have opened the next era of condensed matter physics after graphene and three-dimensional topological insulators. Howev-er, it is not easy to obtain a single large-size crystal because there are many nucleations in the preparation process. Here, a bottom-seed CVT growth method is proposed in this paper, and we acquired the large-size, high-quality NbAs single crystals up to 5x4x4 mm3 finally. X-ray diffrac-tion and STEM confirmed that they are tetragonal NbAs, which the key is to use seed crystal in vertical growth furnace. Notably, the photoelectric properties of the crystal are obtained under the existing conditions, which paves the way for the follow-up work.

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Seeded Chemical Vapor Transport Growth of Cu₂OSeO₃

Cited by 11 publications

References 38 publications

Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

Magnetic studies of monoclinic Cu₄O(SeO₃)₃, a copper-oxo-selenite derivative

Preparation of NbAs Single Crystal by the Seed Growth Process

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Seeded Chemical Vapor Transport Growth of Cu2OSeO3

Cited by 11 publications

References 38 publications

Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction

Magnetic studies of monoclinic Cu4O(SeO3)3, a copper-oxo-selenite derivative

Preparation of NbAs Single Crystal by the Seed Growth Process

Contact Info

Product

Resources

About

Seeded Chemical Vapor Transport Growth of Cu₂OSeO₃

Magnetic studies of monoclinic Cu₄O(SeO₃)₃, a copper-oxo-selenite derivative