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1. Dexterous magnetic manipulation of conductive non-magnetic objects

   https://doi.org/10.1038/s41586-021-03966-6  

   Pham, Lan N.; Tabor, Griffin F.; Pourkand, Ashkan; Aman, Jacob L.; Hermans, Tucker; Abbott, Jake J. (October 2021, Nature)
2. Influence of a dispersion of magnetic and non-magnetic nanoparticles on the magnetic Fredericksz transition of 5CB

   Mouhli, Ahmaed; Ayeb, Habib; Othman, Tahar; Fresnais, Jérôme; Dupuis, Vincent; Nemitz, Ian R.; Pendery, Joel S.; Rosenblatt, Charles; Sandre, Olivier; Lacaze, Emmanuelle (July 2017, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics)

   Long time ago, Brochard and de Gennes predicted the possibility of significantly decreasing the critical magnetic feld of the Fredericksz transition (the magnetic Fredericksz threshold) in a mixture of nematic liquid crystals and ferromagnetic particles, the so-called ferronematics. This phenomenon has rarely been measured, usually due to soft homeotropic anchoring induced at the nanoparticle surface. Here we present an optical study of the magnetic Fredericksz transition combined with a light scattering study of the classical nematic liquid crystal, 5CB, doped with 6 nm diameter magnetic and non-magnetic nanoparticles. Surprisingly, for both nanoparticles, we observe at room temperature a net decrease of the threshold field of the Fredericksz transition at low nanoparti cle concentrations, which appears associated with a coating of the nanoparticles by a brush of polydimethylsiloxane copolymer chains inducing planar anchoring of the director on the nanoparticle surface. Moreover the magnetic Fredericksz threshold exhibits non-monotonic behaviour as a function of the nanoparticle concentration for both types of nanoparticles, first decreasing down to a value from 23% to 31% below that of pure 5CB, then increasing with a further increase of nanoparticle concentration. This is interpreted as an aggregation starting at around 0.02 weight fraction that consumes more isolated nanoparticles than those introduced when the concentration is increased above c = 0:05 weight fraction (volume fraction 3:5 x 10^-2). This shows the larger effect of isolated nanoparticles on the threshold with respect to aggregates. From dynamic light scattering measurements we deduced that, if the decrease of the magnetic threshold when the nanoparticle concentration increases is similar for both kinds of nanoparticles, the origin of this decrease is different for magnetic and non-magnetic nanoparticles. For non-magnetic nanoparticles, the behavior may be associated with a decrease of the elastic constant due to weak planar anchoring. For magnetic nanoparticles there are non-negligible local magnetic interactions between liquid crystal molecules and magnetic nanoparticles, leading to an increase of the average order parameter. This magnetic interaction thus favors an easier liquid crystal director rotation in the presence of external magnetic field, able to reorient the magnetic moments of the nanoparticles along with the molecules. 

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3. Rotating magnetic nanorods detect minute fluctuations of magnetic field

   https://doi.org/10.1103/PhysRevE.100.051101  

   Palkar, Vaibhav; Aprelev, Pavel; Salamatin, Arthur; Brasovs, Artis; Kuksenok, Olga; Kornev, Konstantin G. (November 2019, Physical Review E)
4. Review of voltage-controlled magnetic anisotropy and magnetic insulator

   https://doi.org/10.1016/j.jmmm.2022.169924  

   Dai, Bingqian; Jackson, Malcolm; Cheng, Yang; He, Haoran; Shu, Qingyuan; Huang, Hanshen; Tai, Lixuan; Wang, Kang (December 2022, Journal of Magnetism and Magnetic Materials)
5. Statistical description of coalescing magnetic islands via magnetic reconnection

   https://doi.org/10.1017/S0022377821001112  

   Zhou, Muni; Wu, David H.; Loureiro, Nuno F.; Uzdensky, Dmitri A. (December 2021, Journal of Plasma Physics)

   The physical picture of interacting magnetic islands provides a useful paradigm for certain plasma dynamics in a variety of physical environments, such as the solar corona, the heliosheath and the Earth's magnetosphere. In this work, we derive an island kinetic equation to describe the evolution of the island distribution function (in area and in flux of islands) subject to a collisional integral designed to account for the role of magnetic reconnection during island mergers. This equation is used to study the inverse transfer of magnetic energy through the coalescence of magnetic islands in two dimensions. We solve our island kinetic equation numerically for three different types of initial distribution: Dirac delta, Gaussian and power-law distributions. The time evolution of several key quantities is found to agree well with our analytical predictions: magnetic energy decays as $$\tilde {t}^{-1}$$ , the number of islands decreases as $$\tilde {t}^{-1}$$ and the averaged area of islands grows as $$\tilde {t}$$ , where $$\tilde {t}$$ is the time normalised to the characteristic reconnection time scale of islands. General properties of the distribution function and the magnetic energy spectrum are also studied. Finally, we discuss the underlying connection of our island-merger models to the (self-similar) decay of magnetohydrodynamic turbulence. 

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