Mn12 single molecule magnets deposited on μ-SQUID sensors: the role of interphases and structural modifications

Bellido, Elena; González-Monje, Pablo; Repollés, Ana; Jenkins, M.; Sesé, J.; Drung, D.; Schurig, T.; Awaga, Kunio; Luis, Fernando; Ruiz‐Molina, Daniel

doi:10.1039/c3nr02359a

Cited by 23 publications

(15 citation statements)

References 48 publications

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“…To reach the required accurate positioning of the nanosheet, our preliminary protocol will now have to be reproduced using scanning probe lithography techniques, thus depositing extremely small quantity of materials. Although challenging, this appears feasible since these techniques have been able to deposit a controlled number of isolated magnetic molecules on the most sensitive areas of other solid‐state devices such as μ‐SQUID or μ‐Hall sensors. An alternative procedure for the formation of the nanosheets locally at the nanoconstriction would be the use of dip‐pen nanolithography with microfluidic pens, allowing femtoliter chemistry on surfaces by handling and mixing femtolitre volumes of reagents .…”

Section: Resultsmentioning

confidence: 99%

A Porphyrin Spin Qubit and Its 2D Framework Nanosheets

Urtizberea

Natividad

Alonso

et al. 2018

Adv Funct Materials

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Molecular spin qubits have been shown to reach sufficiently long quantum coherence times to envision their use as hardware in quantum processors. These will however require their implementation in hybrid solid-state devices for which the controlled localization and homogeneous orientation of the molecular qubits will be necessary. An alternative to isolated molecules that can ensure these key aspects is 2D framework in which the qubit would act as node. In this work, it is demonstrated that the isolated metalloporphyrin [Cu(H 4 TCPP)] molecule is a potential spin qubit, and maintains similar quantum coherence as node in a 2D [{CuTCPP}Zn 2 (H 2 O) 2 ] metal-organic framework. Mono-and multilayer deposits of nanosheets of a similar 2D framework are then successfully formed following a modular method based on Langmuir-Schaefer conditions. The orientation of the {CuTCPP} qubit nodes in these nanosheets is homogeneous parallel to the substrate. These nanosheets are also formed with a control over the qubit concentration, i.e., by dilution with the unmetallated porphyrin. Eventually, 2D nanosheets are formed in situ directly on a substrate, through a simple protocol devised to reproduce the Langmuir-Schaefer conditions locally. Altogether these studies show that 2D spin qubit frameworks are ideal components to develop a hybrid quantum computing architecture. and gates first arose in the form of purely organic systems, using either the multiple nuclear spins of rationally selected molecules or the electronic spin(s) of open shell organic molecules bearing one or multiple radicals. The careful design and selection of such organic molecules coupled to sophisticated experiments have allowed implementing realistic quantum operations using ensembles of these. [2] Paramagnetic coordination complexes were later proposed as alternative molecular spin qubits, after it was argued and shown that the molecule electronic spin orientation and quantum superpositions allow to encode quantum bit (qubit) states. [3] Recent improvements in the coherence times of these molecular spin qubits [4] and the unique ability to design molecules with multiple qubits as prototypes of quantum gates [5] have brought this scheme to a point where it becomes reasonable to envision the design of a magnetic quantum processor. A magnetic molecule has even recently been used to implement Grover's quantum algorithm, albeit using its metal ion nuclear spin. [6] One of the advantages of the molecular scheme is that macroscopic numbers of identical qubits are obtained in one sole reaction. While this is appealing for the daunting challenge of scaling to a usable size, common to all proposed schemes, [7] the technology to build a scalable quantum architecture based on molecular qubits is

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Section: Resultsmentioning

confidence: 99%

A Porphyrin Spin Qubit and Its 2D Framework Nanosheets

Urtizberea

Natividad

Alonso

et al. 2018

Adv Funct Materials

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“…Microsusceptometers were also used to detect the ac magnetic susceptibility of just ∼ 9 × 10 7 Mn 12 SMMs arranged as dot-like features containing 3-5 molecular layers 122 . Measurements showed an evident decrease of the magnetic relaxation time compared to that observed in crystalline Mn 12 .…”

Section: Susceptibility Measurementsmentioning

confidence: 99%

NanoSQUIDs: Basics & recent advances

Pérez¹,

Koelle²

2018

Nano Online

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Superconducting Quantum Interference Devices (SQUIDs) are one of the most popular devices in superconducting electronics. They combine the Josephson effect with the quantization of magnetic flux in superconductors. This gives rise to one of the most beautiful manifestations of macroscopic quantum coherence in the solid state. In addition, SQUIDs are extremely sensitive sensors allowing to transduce magnetic flux into measurable electric signals. As a consequence, any physical observable that can be converted into magnetic flux, e.g., current, magnetization, magnetic field or position, becomes easily accessible to SQUID sensors. In the late 1980's it became clear that downsizing the dimensions of SQUIDs to the nanometric scale would encompass an enormous increase of their sensitivity to localized tiny magnetic signals. Indeed, nanoSQUIDs opened the way to the investigation of, e.g., individual magnetic nanoparticles or surface magnetic states with unprecedented sensitivities. The purpose of this review is to present a detailed survey of microscopic and nanoscopic SQUID sensors. We will start by discussing the principle of operation of SQUIDs, placing the emphasis on their application as ultrasensitive detectors for small localized magnetic signals. We will continue by reviewing a number of existing devices based on different kinds of Josephson junctions and materials, focusing on their advantages and drawbacks. The last sections are left for applications of nanoSQUIDs in the fields of scanning SQUID microscopy and magnetic particle characterization, putting special stress on the investigation of individual magnetic nanoparticles.CONTENTS arXiv:1609.06182v4 [cond-mat.supr-con]

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“…Ac susceptibility measurements were extended to the region of very low temperatures by using a home-made micro-SQUID susceptometer 42 . The micro-SQUID has a gradiometric design, with two 30 μm wide Nb loops that act as the pick-up coils of the susceptometer.…”

Section: Methodsmentioning

confidence: 99%

Quantum Monte Carlo simulations of a giant {Ni21Gd20} cage with a S = 91 spin ground state

et al. 2018

Self Cite

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The detailed analysis of magnetic interactions in a giant molecule is difficult both because the synthesis of such compounds is challenging and the number of energy levels increases exponentially with the magnitude and number of spins. Here, we isolated a {Ni21Gd20} nanocage with a large number of energy levels (≈5 × 1030) and used quantum Monte Carlo (QMC) simulations to perform a detailed analysis of magnetic interactions. Based on magnetization measurements above 2 K, the QMC simulations predicted very weak ferromagnetic interactions that would give a record S = 91 spin ground state. Low-temperature measurements confirm the spin ground state but suggest a more complex picture due to the single ion anisotropy; this has also been modeled using the QMC approach. The high spin and large number of low-lying states lead to a large low-field magnetic entropy (14.1 J kg−1 K−1 for ΔH = 1 T at 1.1 K) for this material.

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Mn12 single molecule magnets deposited on μ-SQUID sensors: the role of interphases and structural modifications

Cited by 23 publications

References 48 publications

A Porphyrin Spin Qubit and Its 2D Framework Nanosheets

A Porphyrin Spin Qubit and Its 2D Framework Nanosheets

NanoSQUIDs: Basics & recent advances

Quantum Monte Carlo simulations of a giant {Ni21Gd20} cage with a S = 91 spin ground state

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