This title appears in the Scientific Report :
2021
Please use the identifier:
http://hdl.handle.net/2128/28677 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.103.024447 in citations.
Destruction of long-range magnetic order in an external magnetic field and the associated spin dynamics in Cu 2 GaBO 5 and Cu 2 AlBO 5 ludwigites
Destruction of long-range magnetic order in an external magnetic field and the associated spin dynamics in Cu 2 GaBO 5 and Cu 2 AlBO 5 ludwigites
The quantum spin systems Cu2MBO5 (M = Al, Ga) with the ludwigite crystal structure consist of astructurally ordered Cu2+ sublattice in the form of three-leg ladders, interpenetrated by a structurally disorderedsublattice with a statistically random site occupation by magnetic Cu2+ and nonmagnetic Ga...
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Personal Name(s): | Kulbakov, A. A. |
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Sarkar, R. / Janson, O. / Dengre, S. / Weinhold, T. / Moshkina, E. M. / Portnichenko, P. Y. / Luetkens, H. / Yokaichiya, F. / Sukhanov, A. S. / Eremina, R. M. / Schlender, Ph. / Schneidewind, A. / Klauss, H.-H. / Inosov, D. S. (Corresponding author) | |
Contributing Institute: |
JCNS-4; JCNS-4 Streumethoden; JCNS-2 Heinz Maier-Leibnitz Zentrum; MLZ JCNS-FRM-II; JCNS-FRM-II |
Published in: | Physical Review B Physical review / B, 103 103 (2021 2021) 2 2, S. 024447 024447 |
Imprint: |
Woodbury, NY
Inst.
2021
|
DOI: |
10.1103/PhysRevB.103.024447 |
Document Type: |
Journal Article |
Research Program: |
Jülich Centre for Neutron Research (JCNS) (FZJ) Materials – Quantum, Complex and Functional Materials |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.103.024447 in citations.
The quantum spin systems Cu2MBO5 (M = Al, Ga) with the ludwigite crystal structure consist of astructurally ordered Cu2+ sublattice in the form of three-leg ladders, interpenetrated by a structurally disorderedsublattice with a statistically random site occupation by magnetic Cu2+ and nonmagnetic Ga3+ or Al3+ ions. Amicroscopic analysis based on density-functional-theory calculations for Cu2GaBO5 reveals a frustrated quasitwo-dimensional spin model featuring five inequivalent antiferromagnetic exchanges. A broad low-temperature11B nuclear magnetic resonance points to a considerable spin disorder in the system. In zero magnetic field,antiferromagnetic order sets in below TN ≈ 4.1 K and ∼2.4 K for the Ga and Al compounds, respectively. Fromneutron diffraction, we find that the magnetic propagation vector in Cu2GaBO5 is commensurate and lies on theBrillouin-zone boundary in the (H0L) plane, qm = (0.45, 0, −0.7), corresponding to a complex noncollinearlong-range ordered structure with a large magnetic unit cell. Muon spin relaxation is monotonic, consisting of afast static component typical for complex noncollinear spin systems and a slow dynamic component originatingfrom the relaxation on low-energy spin fluctuations. Gapless spin dynamics in the form of a diffuse quasielasticpeak is also evidenced by inelastic neutron scattering. Most remarkably, application of a magnetic field above1 T destroys the static long-range order, which is manifested in the gradual broadening of the magnetic Braggpeaks. We argue that such a crossover from a magnetically long-range ordered state to a spin-glass regime mayresult from orphan spins on the structurally disordered magnetic sublattice, which are polarized in magnetic fieldand thus act as a tuning knob for field-controlled magnetic disorder. |