Macroscopic Quantum Tunneling of Magnetization of Single Ferrimagnetic Nanoparticles of Barium Ferrite

Wernsdorfer, Wolfgang; Orozco, E. Bonet; Hasselbach, K.; Benoı̂t, A.; Mailly, D.; Kubo, Ozora; Nakano, Hiroshi; Barbara, B.

doi:10.1103/physrevlett.79.4014

Cited by 229 publications

(192 citation statements)

References 31 publications

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“…We have seen in the previous studies [9][10][11][12] that the magnetic anisotropy is often dominated by second-order anisotropy terms. However, for nearly symmetric shapes, fourth-order terms 1 can be comparable or even dominant with respect to the second-order terms.…”

Section: Uniform Rotation With Cubic Anisotropymentioning

confidence: 99%

Magnetisation reversal by uniform rotation (Stoner–Wohlfarth model) in FCC cobalt nanoparticles

Wernsdorfer

Thirion

Demoncy

et al. 2002

Journal of Magnetism and Magnetic Materials

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Section: Uniform Rotation With Cubic Anisotropymentioning

confidence: 99%

Magnetisation reversal by uniform rotation (Stoner–Wohlfarth model) in FCC cobalt nanoparticles

Wernsdorfer

Thirion

Demoncy

et al. 2002

Journal of Magnetism and Magnetic Materials

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“…For instance, the magnetic signal of one nanoparticle is detectable if placed on the junction of a micrometer sized superconducting quantum interference device (micro-SQUID) 24 . We present a novel setup for ESR measurements, which combines the high spin sensitivity of an on-chip micro-SQUID and the flexibility of a coplanar waveguide for microwave excitation.…”

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confidence: 99%

Sensitive spin detection using an on-chip SQUID-waveguide resonator

Yue

Chen

Barreda

et al. 2017

Applied Physics Letters

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Precise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a novel setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated from 20 nm Nb thin film, allowing high magnetic field operation with the field applied parallel to the chip. We observe a resonance signal between the first and third excited states of Gd spins S = 7/2 in a CaWO 4 crystal, relevant for state control in multi-level systems.Solid state spin-based qubits are studied for quantum computing due to their relatively long coherence time 1,2 . Typical implementations of these qubits are molecule-based magnets 3-6 , nitrogen-vacancy (NV) centers in diamond 7 and quantum spins in crystals 8-11 . These spin-based qubits are designed such that the spins are well separated in the crystal, leading to an increased decoherence time due to weak spin dipolar interactions.Among the rare-earth ions, S-state lanthanide ions doped in a crystal have a rich energy level structure due to their large spin. Multi-level systems are promising for implementing few-qubits algorithms 12 or as quantum memories [13][14][15][16] . For quantum technology applications, a higher sensitivity electron spin resonance (ESR) measurement is needed to be able to manipulate spins in mesoscopic crystals placed on superconducting chips [17][18][19][20][21] .Compared to other ultra-high sensitivity ESR measurements 22,23 , the use of Josephson junctions can increase significantly the spatial resolution of the magnetic detection while allowing an on-chip implementation. For instance, the magnetic signal of one nanoparticle is detectable if placed on the junction of a micrometer sized superconducting quantum interference device (micro-SQUID) 24 . We present a novel setup for ESR measurements, which combines the high spin sensitivity of an on-chip micro-SQUID and the flexibility of a coplanar waveguide for microwave excitation. Different dc-SQUID implementations were also used to detect molecular 25,26 and diluted 27 spins. In our case, the coupling of the two devices generates a cavity effect, which amplifies the microwave power seen by the spins. When using micro-SQUIDs, the samples are positioned close to their loop for increased sensitivity since the device a) Electronic mail: gy10c@my.fsu.edu b) Electronic mail: ic@magnet.fsu. edu FIG. 1. (color online) Scanning electron micrograph of the device and of the micro-SQUID (inset). The darker (blue) area is the coplanar waveguide with the two Ω-loop shortcircuits between the central line and the lateral ground planes. The microwave excitation is depicted by the curvy arrow and an in-plane field B0 is generated by an external coil. The SQUIDs share a common ground (sketched as a white rectangle). Each SQUID has one I − V line shown in green for clarity in their narrowest region.can work under in-plane magnetic fields in the range of ∼Tesla [28][29][30] .Using this s...

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“…Note that the degeneracies of the other level crossings are also removed by internal fields fluctuations. Magnetic measurements were made at 0.04 < T < 1 K and for µ 0 H < 2 T, with a micro-SQUID magnetometer [4] allowing field sweep rates up to 1 T/s. The crystal is first saturated in a large positive field applied along the c−axis µ 0 H sat ≈ 0.3 T, and then the field H z is swept between ±H sat .…”

mentioning

confidence: 99%

Tunneling of magnetization versus spin–phonon and spin–spin transitions in LiY0.998Ho0.002F4

Giraud

Wernsdorfer

Ткачук

et al. 2002

Journal of Magnetism and Magnetic Materials

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Strong hyperfine coupling in a 0.2% Holmium doped LiYF 4 single crystal induces staircaselike hysteresis loops of the magnetization at very low temperatures. The field sweep rate dependence of hysteresis loops allows the study of two different regimes in the magnetic relaxation of these weakly coupled magnetic moments. At slow field sweep rates, quantum tunneling of the magnetization occurs at avoided level crossings in the low-energy scheme of a single ion Ho 3+ . At faster sweep rates, nonequilibrated spin-phonon and spin-spin transitions, mediated by weak dipolar interactions, lead to magnetization oscillations and additional steps.

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Macroscopic Quantum Tunneling of Magnetization of Single Ferrimagnetic Nanoparticles of Barium Ferrite

Cited by 229 publications

References 31 publications

Magnetisation reversal by uniform rotation (Stoner–Wohlfarth model) in FCC cobalt nanoparticles

Magnetisation reversal by uniform rotation (Stoner–Wohlfarth model) in FCC cobalt nanoparticles

Sensitive spin detection using an on-chip SQUID-waveguide resonator

Tunneling of magnetization versus spin–phonon and spin–spin transitions in LiY0.998Ho0.002F4

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