The use of paramagnetic molecules as cryogenic coolants usually requires relatively large fields to obtain a practical cooling effect. Thus, research for magnetic molecular materials with larger MCEs in fields of ≤ 2 T is the central science. In this work, the crystal structure, magnetic susceptibility and isothermal magnetization for inorganic framework material GdF 3 were measured, and the isothermal entropy change was evaluated up to 9 T. Thanks to combination of the large isotropic spin of Gd 3+ , the dense structure and the weak ferromagnetic interaction, an extremely large -∆S m for GdF 3 was observed up to 528 mJ cm -3 K -1 for ∆µ 0 H = 9 T, proving itself to be an exceptional cryogenic magnetic coolant.The magnetocaloric effect of a inorganic framework material with repeating unit of GdF 3 has been experimentally studied using isothermal magnetization and heat capacity measurements. The maximum entropy change -∆S max reaches 74.8 J kg -1 K -1 or 528 mJ cm -3 K -1 for ∆H = 9 T and T = 1.8 K.

The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4(-) ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl(-) and NO3(-) were incorporated in the reaction instead of ClO4(-), {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl(-) and NO3(-) stimulus. To our knowledge, it is the first time that the linear M-O-M' fashion and the unique μ8-ClO4(-) mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg(-1) K(-1) and mJ cm(-3) K(-1) on account of the weak antiferromagnetic exchange, the high N(Gd)/M(W) ratio (magnetic density), and the relatively compact crystal lattice (mass density).

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Mn 3 Sn has recently attracted considerable attention as a magnetic Weyl semimetal exhibiting concomitant transport anomalies at room temperature. The topology of the electronic bands, their relation to the magnetic ground state and their nonzero Berry curvature lie at the heart of the problem. The examination of the full magnetic Hamiltonian reveals otherwise hidden aspects of these unusual physical properties. Here, we report the full spin wave spectra of Mn 3 Sn measured over a wide momentum -energy range by the inelastic neutron scattering technique. Using a linear spin wave theory, we determine a suitable magnetic Hamiltonian which not only explains the experimental results but also stabilizes the low-temperature helical phase, consistent with our DFT calculations. The effect of this helical ordering on topological band structures is further examined using a tight-binding method, which confirms the elimination of Weyl points in the helical phase. Our work provides a rare example of the intimate coupling between the electronic and spin degrees of freedom for a magnetic Weyl semimetal system. 1 arXiv:1811.07549v1 [cond-mat.str-el]

Giant magnetoresistance effects in intermetallic compoundsSechovsky, V.; Havela, L.; Prokes, K.; Nakotte, H.; de Boer, F.R.; Bruck, E.H. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Giant magnetoresistance (GMR) effects are observed in several classes of bulk magnetic materials.The resistance changes at metamagnetic transitions connected with reorientation of 4f moments are only moderate due to the relatively weak coupling of the 4f and conduction electrons. Much larger GMR effects can be achieved by mechanisms involving the d states (RhFe, RCo&, though the most spectacular resistance variations are connected with metamagnetic transitions in U-intermetallic antiferromagnets. This phenomenon can 'be interpreted as due to Fermi surface gapping (due to magnetic superzones) and/or due to spin-dependent scattering in analogy with magnetic multilayers.