Contribution of spin pairs to the magnetic response in a dilute dipolar ferromagnet

Gannarelli, C. M. S.; Silevitch, D. M.; Rosenbaum, T. F.; Aeppli, G.; Fisher, A. J.

doi:10.1103/physrevb.86.014420

Cited by 5 publications

(6 citation statements)

References 31 publications

(69 reference statements)

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“…Magnetic dilution is a useful approach to investigate the magnetic properties of a given SMM without the influence of its magnetic neighbors . Once crystallized in an isomorphous diamagnetic matrix, the SMM behavior is generally optimized as intermolecular interactions that are likely to create additional and damaging pathways for the magnetic relaxation are suppressed .…”

Section: Resultsmentioning

confidence: 99%

Magnetic Slow Relaxation in a Metal–Organic Framework Made of Chains of Ferromagnetically Coupled Single‐Molecule Magnets

Huang

Garcia

Badiane

et al. 2018

Chemistry A European J

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We report the study of a Dy-based metal-organic framework (MOF) with unprecedented magnetic properties. The compound is made of nine-coordinated Dy magnetic building blocks (MBBs) with poor intrinsic single-molecule magnet behavior. However, the MOF architecture constrains the MBBs in a one-dimensional structure that induces a ferromagnetic coupling between them. Overall, the material shows a magnetic slow relaxation in absence of external static field and a hysteretic behavior at 0.5 K. Low-temperature magnetic studies, diamagnetic doping, and ab initio calculations highlight the crucial role played by the Dy-Dy ferromagnetic interaction. Overall, we report an original magnetic object at the frontier between single-chain magnets and single-molecule magnets that host intrachain couplings that cancel quantum tunneling between the MBBs. This compound is evidence that a bottom-up approach through MOF design can induce spontaneous organization of MBBs able to produce remarkable molecular magnetic materials.

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Section: Resultsmentioning

confidence: 99%

Magnetic Slow Relaxation in a Metal–Organic Framework Made of Chains of Ferromagnetically Coupled Single‐Molecule Magnets

Huang

Garcia

Badiane

et al. 2018

Chemistry A European J

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“…Previous work has shown that transverse fields H t applied to LiHo Consistent with classical pinning, the initial softening effect is visible only when cooling in field from high temperature, whereas the high transverse field (2 kOe) hardening is historyindependent and therefore consistent with H t -induced quantum speedup. be probed directly (28,40).…”

Section: Resultsmentioning

confidence: 99%

Using thermal boundary conditions to engineer the quantum state of a bulk magnet

Schmidt

Silevitch

Aeppli

et al. 2014

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

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The degree of contact between a system and the external environment can alter dramatically its proclivity to quantum mechanical modes of relaxation. We show that controlling the thermal coupling of cubic-centimeter-sized crystals of the Ising magnet LiHo x Y 1-x F 4 to a heat bath can be used to tune the system between a glassy state dominated by thermal excitations over energy barriers and a state with the hallmarks of a quantum spin liquid. Application of a magnetic field transverse to the Ising axis introduces both random magnetic fields and quantum fluctuations, which can retard and speed the annealing process, respectively, thereby providing a mechanism for continuous tuning between the destination states. The nonlinear response of the system explicitly demonstrates quantum interference between internal and external relaxation pathways.quantum magnetism | random fields | quantum annealing | quantum information | adiabatic quantum computing T he coupling of a sample to its environment is both a fundamental theoretical concept and a powerful experimental tool in classical thermodynamics. For quantum systems, contact between the internal degrees of freedom and the external world, often referred to as the "bath," can change the measured outcome completely. Typically, such experiments involve a small number of particles sensitive to subtle changes in the external incoherent environment, such as ultracold atoms confined in precisely controlled optical potentials (1-3). With the search for viable solid-state qubits for quantum computing, the control of bath-induced decoherence in solids also has become an important topic for engineers and condensed-matter physicists. Approaches have centered on the nuclear spin bath (4-6), modifying it either with isotopic substitution (7) or radio frequency pulses (8), and on electrical control of the exchange interaction between electron spins in coupled quantum dots (9). The question of the importance of coupling to an external bath, as provided by a cryostat, has not been researched as intensively. Here, we show that by engineering the thermal boundary conditions for a macroscopic magnetic crystal, it is possible to select distinct low temperature states. Conditions of constant energy, as opposed to constant temperature, yield relatively fewer low energy contributions to the fluctuation spectrum and decouple the spin excitations responsible for that spectrum into separate oscillators. The experiments show the importance of thermal heat sinking for quantum annealing, also referred to as adiabatic quantum computation (10-13), as well as new protocols for generating quantum cluster states (14).The LiHo x Y 1-x F 4 family of insulating magnetic salts provides a physical manifestation of the simplest quantum mechanical spin model, the Ising model in transverse field (15). Pure LiHoF 4 (16, 17) is a ferromagnet with Curie temperature, T C = 1.53 K. External magnetic fields can produce the longitudinal and transverse fields in the model, chemical substitution of Ho 3+ ions by the non...

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“…The field scale H c can be connected to the microscopic properties of Li(Ho,Y)F 4 by comparison with an exact diagonalization of the full Hamiltonian for a pair of coupled Ho 3+ atoms 37 , where there is a crossing of the lowest coupled electronuclear levels for nearest-neighbor spins positioned in the ab plane at (100) or (010) relative to each other. The effects of these pairwise level crossings can be seen in the measured linear longitudinal susceptibility χ zz ( H t ) 24,37 . The characteristic dynamics of the pairwise susceptibility shift as a function of classical (temperature) and quantum-mechanical (transverse field) energy scales, moving from 9 kOe at 70 mK to 5 kOe at 150 mK.…”

Section: Discussionmentioning

confidence: 99%

Tuning high-Q nonlinear dynamics in a disordered quantum magnet

et al. 2019

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Quantum states cohere and interfere. Atoms arranged imperfectly in a solid rarely display these properties. Here we demonstrate an exception in a disordered quantum magnet that divides itself into nearly isolated subsystems. We probe these coherent spin clusters by driving the system nonlinearly and measuring the resulting hole in the linear spectral response. The Fano shape of the hole encodes the incoherent lifetime as well as coherent mixing of the localized excitations. For the Ising magnet LiHo 0.045 Y 0.955 F 4 , the quality factor Q for spectral holes can be as high as 100,000. We tune the dynamics by sweeping the Fano mixing parameter q through zero via the ac pump amplitude as well as a dc transverse field. The zero crossing of q is associated with a dissipationless response at the drive frequency. Identifying localized two-level systems in a dense and disordered magnet advances the search for qubit platforms emerging from strongly interacting, many-body systems.

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Contribution of spin pairs to the magnetic response in a dilute dipolar ferromagnet

Cited by 5 publications

References 31 publications

Magnetic Slow Relaxation in a Metal–Organic Framework Made of Chains of Ferromagnetically Coupled Single‐Molecule Magnets

Magnetic Slow Relaxation in a Metal–Organic Framework Made of Chains of Ferromagnetically Coupled Single‐Molecule Magnets

Using thermal boundary conditions to engineer the quantum state of a bulk magnet

Tuning high-Q nonlinear dynamics in a disordered quantum magnet

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