Designing new ferrite/manganite nanocomposites

Abstract

Two kinds of nanocomposites of transition metal oxides were synthesized and investigated. Each nanocomposite comprises nanoparticles of La0.67Ca0.33MnO3 and CoFe2O4 in similar volume fractions, however arranged with different morphologies. The temperature-dependent magnetic and electrical properties of the two systems are found to greatly differ, suggesting different degrees of interaction and coupling of their constituents. This is confirmed by magnetic field-dependent experiments, which reveal contrasted magnetization reversal and magnetoresistance in the systems. We discuss this morphology-physical property relationship, and the possibility to further tune the magnetism and magneto-transport in such nanocomposites.

Magnetic hyperthermia efficiency and MRI contrast sensitivity of colloidal soft/hard ferrite nanoclusters

“…For the bi-magnetic NCs we found also high Ms (97 emu/g) but coercivity was decreased (close to 700 Oe). However, the most interesting feature of the loop is the fact that is no longer smooth, presenting a shrinkage at lower fields.That means that the two phases do not reverse at the same nucleation field, as the soft phase nucleates the reversal at significantly lower fields and the switching is characterized by an inhomogeneous reversal[27,34,41]. The symmetric shape with respect of the origin demonstrates the absence of exchange bias, as the MnFe2O4 and CoFe2O4 nanoparticles are not in intimate contact within each cluster due to the layer of oleylamine on their surface.…”

Magnetic properties of ε iron(III) oxide nanorod arrays functionalized with gold and copper(II) oxide

“…the normal to the rod axis in the target case. The remanent curves allow purely irreversible magnetization changes to be investigated and are more appropriate to describe the switching process with respect to the hysteresis loops, that encompass both reversible and irreversible processes [54]. From each DCD curve, the remanent coercivity Hcr, defined as the field at which the remanence is zero, was determined and its dependence as a function of the angle  (i.e., Hcr vs. ) is reported in Fig.…”

Fluoride ion assisted growth of hierarchical flowerlike nanostructures of Co/Ni ferrites and their magnetoresistive response

“…5,6 They also show interesting magnetic and transport properties such as colossal magnetoresistance (CMR), tunnel magnetoresistance (TMR), magnetodielectric and magnetoelectric effects which are directly applicable to spintronic devices. [7][8][9] Among these materials, cobalt ferrite (CoFe 2 O 4 ) with an inverse spinel structure shows attractive magnetodielectric properties with high magnetic anisotropy and chemical stability. 10,11 Nickel ferrite (NiFe 2 O 4 ) being ferrimagnetic, on the other hand, possesses magnetoresistive nature, which is signicantly inuenced by variation in particle size and shapes.…”