Controlling nickel nanoparticle size in an organic/metal–organic matrix through the use of different solvents

Abstract

(2013) 'Controlling nickel nanoparticle size in an organic/metal-organic matrix through the use of di erent solvents. ', Nanoscale., 5 (24). pp. 12212-12223. Further information on publisher's website:http://dx.doi.org/10.1039/c3nr04883gPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. (0) atoms from the Ni(COD)2. Materials are characterised with a combination of X-ray diffraction, electron microscopy and magnetometry and it is found that samples made using a halocarbon solvent resulted in clustered bulk Ni particles (size ≤ 10 nm) with anomalously high superparamagnetic blocking temperatures. Using an isocyanide solvent produces smaller (size ∼ 1 nm), well dispersed particles that show little evidence of superparamagnetic blocking in the range of temperatures investigated (> 2 K). In all samples there is another component which dominates the magnetic response at low temperatures and shows an interesting temperature dependent scaling behaviour when plotted as M vs B/T which we believe is related to the organo-metallic matrix that the particles are trapped within. We propose that the enhanced blocking temperature of particles synthesised using halocarbon solvents can be attributed to inter-particle dipolar interactions and nanoparticle-matrix exchange interactions.

No evidence for room temperature ferromagnetism in the high temperature metal-organic material: Ni2TCNQ

“…Previous work by us on nominal Ni 2 A salts showed that, when swapping the TCNQ for tetrafluro-TCNQ (TCNQF 4 ), a black powder was formed with similar magnetic properties to that observed within Ni 2 TCNQ [13]. However, the magnetic properties showed a solvent dependency and when a nitrilebased solvent was used, this caused there to be a significant change in the room temperature magnetism.…”

Structure and size dependence of the magnetic properties of Ni@C nanocomposites

“…Ni nanoparticles encapsulated in a carbon matrix, Ni@C nanocomposites, were investigated in Refs. [20][21][22][23][24][25][26][27][28]. Depending on used synthetic techniques, Ni@C nanocomposites can have different carbon structures, morphology and magnetic characteristics.…”

“…Almost all prior works dedicated to the investigation of Ni@C nanocomposites [24][25][26][27] point at the lower values of saturation magnetization comparing to that of bulk Ni. The possible reasons of magnetization reduction with decrease in nanoparticle size are discussed in Refs.…”