Abstract
The term ‘molecular magnet’ generally refers to a molecular entity containing several magnetic ions whose coupled spins generate a collective spin, S (ref. 1). Such complex multi-spin systems provide attractive targets for the study of quantum effects at the mesoscopic scale. In these molecules, the large energy barriers between collective spin states can be crossed by thermal activation or quantum tunnelling, depending on the temperature or an applied magnetic field2,3,4. There is the hope that these mesoscopic spin states can be harnessed for the realization of quantum bits—‘qubits’, the basic building blocks of a quantum computer—based on molecular magnets5,6,7,8. But strong decoherence9 must be overcome if the envisaged applications are to become practical. Here we report the observation and analysis of Rabi oscillations (quantum oscillations resulting from the coherent absorption and emission of photons driven by an electromagnetic wave10) of a molecular magnet in a hybrid system, in which discrete and well-separated magnetic
clusters are embedded in a self-organized non-magnetic environment. Each cluster contains 15 antiferromagnetically coupled S = 1/2 spins, leading to an S = 1/2 collective ground state11,12,13. When this system is placed into a resonant cavity, the microwave field induces oscillatory transitions between the ground and excited collective spin states, indicative of long-lived quantum coherence. The present observation of quantum oscillations suggests that low-dimension self-organized qubit networks having coherence times of the order of 100 μs (at liquid helium temperatures) are a realistic prospect.
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References
Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, Oxford, UK, 2006)
Barbara, B. et al. Mesoscopic quantum tunneling of the magnetization. J. Magn. Magn. Mater. 140–144, 1825–1828 (1995)
Thomas, L. et al. Macroscopic quantum tunneling of magnetization in a single crystal of nanomagnets. Nature 383, 145–147 (1996)
Friedman, J. R. et al. Macroscopic measurements of resonant magnetization tunneling in high spin molecules. Phys. Rev. Lett. 76, 3830–3833 (1996)
Leuenberger, M. N. & Loss, D. Quantum computing in molecular magnets. Nature 410, 789–793 (2001)
Aharonov, D., Kitaev, A. & Preskill, J. Fault-tolerant quantum computation with long-range correlated noise. Phys. Rev. Lett. 96, 050504 (2006)
Stamp, P. C. E. & Tupitsyn, I. S. Coherence window in the dynamics of quantum nanomagnets. Phys. Rev. B 69, 014401 (2004)
Morello, A., Stamp, P. C. E. & Tupitsyn, I. S. Pairwise decoherence in coupled spin qubit networks. Phys. Rev. Lett. 97, 207206 (2006)
Prokof’ev, N. V. & Stamp, P. C. E. Theory of the spin bath. Rep. Prog. Phys. 63, 669–726 (2000)
Rabi, I. I. Space quantization in a gyrating magnetic field. Phys. Rev. 51, 652–654 (1937)
Müller, A. & Döring, J. A novel heterocluster with D 3-symmetry containing twenty-one core atoms: [AsIII 6VIV 15O42(H2O)]6- . Angew. Chem. Int. Edn Engl. 27, 1721 (1988)
Gatteschi, D., Pardi, L., Barra, A. L., Müller, A. & Döring, J. Layered magnetic structure of a metal cluster ion. Nature 354, 463–465 (1991)
Barbara, B. On the richness of supra-molecular chemistry and its openings in physics. J. Mol. Struct. 656, 135–140 (2003)
Wernsdorfer, W., Müller, A., Mailly, D. & Barbara, B. Resonant photon absorption in the low spin molecule V15 . Europhys. Lett. 66, 861–867 (2004)
Ardavan, A. et al. Will spin-relaxation times in molecular magnets permit quantum information processing? Phys. Rev. Lett. 98, 057201 (2007)
Wernsdorfer, W. A long-lasting phase. Nature Mater. 6, 174–176 (2007)
Mehring, M., Mende, J. & Scherer, W. Entanglement between an electron and a nuclear spin ½. Phys. Rev. Lett. 90, 153001 (2003)
Morton, J. J. L. et al. Bang–bang control of fullerene qubits using ultrafast phase gates. Nature Phys. 2, 40–43 (2006)
Bertaina, S. et al. Rare earth solid state qubits. Nature Nanotechnol. 2, 39–42 (2007)
Nellutla, S. et al. Coherent manipulation of electron spins up to ambient temperatures in Cr5+ (S = 1/2) doped K3NbO8 . Phys. Rev. Lett. 99, 137601 (2007)
Chiorescu, I., Wernsdorfer, W., Müller, A., Bögge, H. & Barbara, B. Butterfly hysteresis loop and dissipative spin reversal in the S = 1/2, V15 molecular complex. Phys. Rev. Lett. 84, 3454–3457 (2000)
De Raedt, H. D., Miyashita, S., Michielsen, K. & Machida, M. Dzyaloshinskii-Moriya interactions and adiabatic magnetization dynamics in molecular magnets. Phys. Rev. B 70, 064401 (2004)
Chaboussant, G. et al. Mechanism of ground-state selection in the frustrated molecular spin cluster V15 . Europhys. Lett. 66, 423–429 (2004)
Tarantul, A., Tsukerblat, B. & Müller, A. Static magnetization of V15 cluster at ultra-low temperatures: Precise estimation of antisymmetric exchange. Inorg. Chem. 46, 161–169 (2007)
Tsukerblat, B., Tarantul, A. & Müller, A. Low temperature EPR spectra of the mesoscopic cluster V15: The role of antisymmetric exchange. J. Chem. Phys. 125, 054714 (2006)
Dzyaloshinsky, I. A thermodynamic theory of “weak” ferromagnetism of antiferromagnetics. J. Phys. Chem. Solids 4, 241–255 (1958)
Moriya, T. Anisotropic superexchange interactions and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960)
Volkmer, D. et al. Towards nanodevices: Synthesis and characterization of the nanoporous surfactant-encapsulated keplerate (DODA)40(NH4)2[(H2O) n ⊂ Mo132O372(CH3COO)30(H2O)72]. J. Am. Chem. Soc. 122, 1995–1998 (2000)
Prokof'ev, N. V. & Stamp, P. C. E. Quantum relaxation of magnetisation in magnetic particles. J. Low Temp. Phys. 104, 143–210 (1996)
Hartmann-Boutron, F., Politi, P. & Villain, J. Tunneling and magnetic relaxation in mesoscopic molecules. Int. J. Mod. Phys. B 10, 2577–2637 (1996)
Acknowledgements
We acknowledge I. Chiorescu from NHMFL-FSU, Tallahassee, USA, for discussions. We thank M.-N. Collomb for help in processing samples for EPR measurements, and G. Desfonds for technical support. B.B. and A.M. thank the European Research Council for support through network projects MAGMANet, MolNanoMag, QueMolNa and INTAS; A.M. thanks the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie for support; and B.T. and A.M. thank the German–Israeli Foundation for Scientific Research and Development for support.
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Bertaina, S., Gambarelli, S., Mitra, T. et al. Quantum oscillations in a molecular magnet. Nature 453, 203–206 (2008). https://doi.org/10.1038/nature06962
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DOI: https://doi.org/10.1038/nature06962
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