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Title: Microelectromechanical systems integrating molecular spin crossover actuators

Abstract

Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H{sub 2}B(pz){sub 2}){sub 2}(phen)] (H{sub 2}B(pz){sub 2} = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δf{sub r} = −0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

Authors:
 [1];  [2]; ; ; ;  [1]; ; ; ; ;  [3]
  1. LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France)
  2. (France)
  3. LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France)
Publication Date:
OSTI Identifier:
22594344
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTUATORS; ALLOCATIONS; BORATES; CONTROL; COUPLING; HIGH SPIN STATES; MAGNETIC FIELDS; MEMS; NEMS; OPTIMIZATION; PARTICLE TRACKS; RESONANCE; SILICON; SPIN; THIN FILMS

Citation Formats

Manrique-Juarez, Maria D., LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse, Rat, Sylvain, Salmon, Lionel, Molnár, Gábor, Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr, Mathieu, Fabrice, Saya, Daisuke, Séguy, Isabelle, Leïchlé, Thierry, and Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr. Microelectromechanical systems integrating molecular spin crossover actuators. United States: N. p., 2016. Web. doi:10.1063/1.4960766.
Manrique-Juarez, Maria D., LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse, Rat, Sylvain, Salmon, Lionel, Molnár, Gábor, Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr, Mathieu, Fabrice, Saya, Daisuke, Séguy, Isabelle, Leïchlé, Thierry, & Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr. Microelectromechanical systems integrating molecular spin crossover actuators. United States. doi:10.1063/1.4960766.
Manrique-Juarez, Maria D., LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse, Rat, Sylvain, Salmon, Lionel, Molnár, Gábor, Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr, Mathieu, Fabrice, Saya, Daisuke, Séguy, Isabelle, Leïchlé, Thierry, and Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr. 2016. "Microelectromechanical systems integrating molecular spin crossover actuators". United States. doi:10.1063/1.4960766.
@article{osti_22594344,
title = {Microelectromechanical systems integrating molecular spin crossover actuators},
author = {Manrique-Juarez, Maria D. and LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse and Rat, Sylvain and Salmon, Lionel and Molnár, Gábor and Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr and Mathieu, Fabrice and Saya, Daisuke and Séguy, Isabelle and Leïchlé, Thierry and Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr},
abstractNote = {Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H{sub 2}B(pz){sub 2}){sub 2}(phen)] (H{sub 2}B(pz){sub 2} = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δf{sub r} = −0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.},
doi = {10.1063/1.4960766},
journal = {Applied Physics Letters},
number = 6,
volume = 109,
place = {United States},
year = 2016,
month = 8
}
  • In this paper, we analyze two types of hysteresis in spin crossover molecular magnets compounds in the framework of the First Order Reversal Curve (FORC) method. The switching between the two stable states in these compounds is accompanied by hysteresis phenomena if the intermolecular interactions are higher than a threshold. We have measured the static thermal hysteresis (TH) and the kinetic light induced thermal hysteresis (LITH) major loops and FORCs for the polycrystalline Fe(II) spin crossover compound [Fe{sub 1−x}Zn{sub x}(bbtr){sub 3}](ClO{sub 4}){sub 2} (bbtr = 1,4-di(1,2,3-triazol-1-yl)butane), either in a pure state (x = 0) or doped with Zn ions (x = 0.33) considering different sweeping rates.more » Here, we use this method not only to infer the domains distribution but also to disentangle between kinetic and static components of the LITH and to estimate the changes in the intermolecular interactions introduced by dopants. We also determined the qualitative relationship between FORC distributions measured for TH and LITH.« less
  • In this article, we present a new microscopic theoretical approach to the description of spin crossover in molecular crystals. The spin crossover crystals under consideration are composed of molecular fragments formed by the spin-crossover metal ion and its nearest ligand surrounding and exhibiting well defined localized (molecular) vibrations. As distinguished from the previous models of this phenomenon, the developed approach takes into account the interaction of spin-crossover ions not only with the phonons but also a strong coupling of the electronic shells with molecular modes. This leads to an effective coupling of the local modes with phonons which is shownmore » to be responsible for the cooperative spin transition accompanied by the structural reorganization. The transition is characterized by the two order parameters representing the mean values of the products of electronic diagonal matrices and the coordinates of the local modes for the high- and low-spin states of the spin crossover complex. Finally, we demonstrate that the approach provides a reasonable explanation of the observed spin transition in the [Fe(ptz){sub 6}](BF{sub 4}){sub 2} crystal. The theory well reproduces the observed abrupt low-spin → high-spin transition and the temperature dependence of the high-spin fraction in a wide temperature range as well as the pronounced hysteresis loop. At the same time within the limiting approximations adopted in the developed model, the evaluated high-spin fraction vs. T shows that the cooperative spin-lattice transition proves to be incomplete in the sense that the high-spin fraction does not reach its maximum value at high temperature.« less