Crystal growth and magnetic behaviour of pure and doped SrCu2(11BO3)2

Dąbkowska, H. A.; Dąbkowski, A.; Luke, G. M.; Dunsiger, S. R.; Haravifard, Sara; Cecchinel, M.; Gaulin, B. D.

doi:10.1016/j.jcrysgro.2007.04.040

Cited by 23 publications

(23 citation statements)

References 14 publications

(20 reference statements)

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“…This was observed previously e.g. in SrCu 2 ( 11 BO 3 ) 2 system [18]. Surprisingly, in the case of the BiCu 2 PO 6 system, we successfully substituted Zn 2 + (ionic radii 0.68Å) for Cu 2 + (ionic radii 0.65Å [19]) at different Zn-doping level (x¼1%, 5%) without any necessary adjustment of the growth conditions.…”

Section: Crystal Growth Of Bisupporting

confidence: 69%

Crystal growth and characterization of the dilutable frustrated spin-ladder compound Bi(Cu1−xZnx)2PO6

Pomjakushina

Shiroka

Deng

et al. 2010

Journal of Crystal Growth

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a b s t r a c tHigh quality centimeter size single crystals of Bi(Cu 1 À x Zn x ) 2 PO 6 (x ¼ 0%, 1%, 5%) have been successfully grown by the Travelling Solvent Floating Zone (TSFZ) technique. The crystals were grown with a rate of 1 mm/h in a gas mixture of 20% O 2 in Ar. Characterization of the single crystal samples by means of optical microscopy, X-ray powder diffraction, X-ray Laue diffraction, neutron diffraction and magnetization measurement are reported. The magnetic susceptibility w spin ðTÞ, measured from 2 to 300 K, passes a broad maximum around 60 K, followed by an exponential decrease towards lower T, and confirm the formation of a spin singlet ground state at low temperature. At low-temperature a paramagnetic Curie-like upturn quantitatively reflect the increasing Zn-doping level.

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Section: Crystal Growth Of Bisupporting

confidence: 69%

Crystal growth and characterization of the dilutable frustrated spin-ladder compound Bi(Cu1−xZnx)2PO6

Pomjakushina

Shiroka

Deng

et al. 2010

Journal of Crystal Growth

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“…The breaking of singlets by the different dopants is supported by DC susceptibility measurements performed on our single crystals with an applied field H = 1 kG ab plane. [21] All three doped samples had much larger Curie tails than the pure sample, indicating the presence of many more free spin-1/2 Cu's in the singlet regime. We have calculated the spin gap, Curie constant and the resulting fraction of free spins by fitting this data to Eq.…”

Section: Discussion and Analysismentioning

confidence: 92%

“…They concluded that implanted muons may liberate spin density in the spin gap regime that spin-freezes at very low temperatures. [21], this seems to be the only paper describing doped single crystals of this system as they have proven to be quite difficult to grow.…”

Section: +mentioning

confidence: 99%

Impurity-induced singlet breaking inSrCu2(BO3)2

et al. 2007

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We have performed µSR studies on single crystals of SrCu2(BO3)2, a quasi-two-dimensional spin system with a spin singlet ground state. We observe two different muon sites which we associate with muons located adjacent to the two inequivalent O sites. One site, presumed to be located in the Cu-O-Cu superexchange path, exhibits a large increase in the frequency shift with decreasing temperature which is unaffected by the singlet formation, indicating that the muon has locally broken the singlet bond. We have also performed µSR on single crystals of SrMg0.05Cu1.95(BO3)2, Sr0.96La0.04Cu2(BO3)2, and Sr0.95Na0.05Cu2(BO3)2. We have found that the frequency shifts of these doped samples are equivalent and contain three branches at low temperatures. Two of these branches map on to the branches observed in the pure sample reasonably well and so we attribute the third branch to effect of the dopants. Specifically, this third branch represents the case when the muon sits at a site in the superexchange path lacking a corresponding singlet, due to it already being broken as a result of doping. This then leads to the conclusion that singlets are broken in this system when it is doped both in and out of the CuBO3 planes.

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“…The SrCu 2 ( 11 BO 3 ) 2 single-crystal sample was cut from the same high-quality single crystal used in previous magnetic neutron scattering experiments (9,19,30). It was grown using a floating-zone image furnace at a rate of 0.2 mm/h in an O 2 atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…A high-quality single crystal of SrCu 2 (BO 3 ) 2 was grown using a floatingzone image furnace and cleaved to a 50 μm × 50 μm × 30-μm sample for highpressure X-ray measurements (30). The sample was placed in a diamond anvil cell using 4:1 methanol:ethanol as a hydrostatic pressure medium and a piece of polycrystalline silver as a manometer; a helium gas membrane provided in situ pressure tuning at cryogenic temperatures (32).…”

Section: Methodsmentioning

confidence: 99%

Emergence of long-range order in sheets of magnetic dimers

Haravifard

Banerjee

Wezel

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Quantum spins placed on the corners of a square lattice can dimerize and form singlets, which then can be transformed into a magnetic state as the interactions between dimers increase beyond threshold. This is a strictly 2D transition in theory, but real-world materials often need the third dimension to stabilize long-range order. We use high pressures to convert sheets of Cu 2+ spin 1/2 dimers from local singlets to global antiferromagnet in the model system SrCu 2 (BO 3 ) 2 . Single-crystal neutron diffraction measurements at pressures above 5 GPa provide a direct signature of the antiferromagnetic ordered state, whereas high-resolution neutron powder and X-ray diffraction at commensurate pressures reveal a tilting of the Cu spins out of the plane with a critical exponent characteristic of 3D transitions. The addition of anisotropic, interplane, spin-orbit terms in the venerable Shastry-Sutherland Hamiltonian accounts for the influence of the third dimension.condensed matter physics | quantum magnetism | phase transition | dimensional cross-over | neutron and X-ray scattering T wo-dimensional systems lie at the boundary between the order-destroying effects of fluctuations in lower dimension and the emergence of true long-range order in higher dimension. How ordered states form and remain stable at finite temperature is a fundamental question that cuts across the sciences. In physics, surfaces, quantum wells, and layered compounds all have provided insights into the peculiar nature of 2D phases, phase transitions, and dimensional cross-over effects. Of particular interest for quantum phase transitions is the theoretically tractable case of interacting magnetic spins placed on a 2D square lattice, the Shastry-Sutherland model (1). The geometry prevents simultaneous satisfaction of all spin-spin coupling terms, leading to a frustrated state that in turn enhances the effects of quantum fluctuations. As the coupling terms are tuned, magnetic order can emerge, but its nature and the potential influence of other sheets of spins in a real physical system have not been probed directly.The Shastry-Sutherland model can be described by the Hamiltonian:where a set of S = 1/2 spins sits on a square lattice and interacts via a regular array of diagonal bonds. This creates a network of dimers with antiferromagnetic intradimer coupling J and interdimer coupling J′. The ground state depends on the ratio of J′=J = x. For x < 0.7, the ground state consists of S = 0 singlets, whereas for x > 0.9 a global antiferromagnetic phase is expected.For intermediate values of x, a variety of locally ordered states has been predicted (2). The first known experimental realization of the ShastrySutherland lattice is SrCu 2 (BO 3 ) 2 (SCBO) (3). The magnetism in SCBO consists of S = 1/2 Cu 2+ ions in well-separated planes whose nearest-neighbor interactions are mediated by in-plane oxygen bonds; layered Cu-O compounds of this kind are of broad interest due to their role in driving phenomena such as high-temperature superconductivity. At ambient...

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Crystal growth and magnetic behaviour of pure and doped SrCu2(11BO3)2

Cited by 23 publications

References 14 publications

Crystal growth and characterization of the dilutable frustrated spin-ladder compound Bi(Cu1−xZnx)2PO6

Crystal growth and characterization of the dilutable frustrated spin-ladder compound Bi(Cu1−xZnx)2PO6

Impurity-induced singlet breaking inSrCu2(BO3)2

Emergence of long-range order in sheets of magnetic dimers

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