Ecofriendly synthesis, crystal chemistry, electrical, and low-temperature magnetic properties of nanoparticles (Li–Cr) for drug delivery and MRI applications

Mixed Li(0.5-x/2)Fe(2.5-x/2)CrxO4 (X = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) nano-ferrite system
was synthesized by using Citrate gel auto-combustion method. Structural
parameters such as lattice constant, hopping length, and X-ray density were
reported and discussed with composition. The surface morphology was presented
and explained with TEM analysis and SAED patterns. XRD patterns
show the prepared samples are single-phase cubic spinel structure and the
average particle size lies between 17 to 27 nm. TEM analysis shows prepared
sample are the crystallite formation in nano-size. DC electrical properties presented
variation with temperature and composition were discussed and studied
well behind the Curie temperature. Magnetic measurements are carryout with
VSM (Vibrating Sample Magnetometer), Observations have shown that magnetic
properties are strongly influenced due to the substitution of Cr3? in
Lithium ferrites. Two samples Li0.5Cr0.6Fe1.9O4 and Li0.5Cr1.0Fe1.5O4 were subjected
to an applied field of 100 Oe between 5 and 375 K temperature for ZFC
and FC (Zero Field Cooled and Field Cooled) measurements of magnetization
which indicated blocking temperature at around 350 K for both samples beyond
which they exhibited super-paramagnetic behavior.