Ferrimagnetic zinc ferrite fine powders

Abstract

Partially hverked h e powders of zinc ferrite (ZnFe;?O$ were produced by chemical aerogel synthesis. These powders showed magnetic ordering at temperatures to 250K. Upon ball milling, a much higher inversion parameter was attain4 yielhg ferrimagnetic powders having small remanence and coercive fields at room temperature. Due to the small mean particle size, superparamagnetic behavior was seen at temperatures above 25K. Powder properties were characterized by x-ray a a c t i o n , electron microscopy, calorimetry, magnetometry, and MOssbauer effect spectroscopy techniques.

Magnetic properties of ZnFe2O4 nanoparticles produced by a low-temperature solid-state reaction method

“…For the ZFC curve with 10 Oe magnetic field applied, spin-glass behavior can be observed obviously, which is compatible with the heat capacity results obtained by Hamdeh et al [18]. But they still have no proof for either the magnetization or Mo¨ssbauer results.…”

“…Spin-glass behavior was also predicted in nanosized ZnFe 2 O 4 particles by Oliver [15][16][17]. And what is more, according to the above reports of ferrimagnetism of ZnFe 2 O 4 nanoparticles, ball-milling process has to be included [4,12,[15][16][17][18][19].…”

“…In recent years, ZnFe 2 O 4 nanoparticles prepared using varied methods, such as traditional ceramic synthesis [16], aerogel procedure [12,15,[17][18][19], low-temperature hydroxide coprecipitation and hydrothermal synthesis [4], have been studied and observed to be ferrimagnetic or superparamagnetic. The origin of the ferrimagnetic properties of ZnFe 2 O 4 and other spinel ferrite nanoparticles was studied using EXAFS [12][13][14] and low-temperature transmission Mo¨ssbauer spectometer (TMS) with applied magnetic field parallel to the direction of gamma rays [15,16].…”

Effect of Nd3+ substitution on structural and electrical properties of nanocrystalline zinc ferrite

“…Various chemical methods such as co-precipitation [18], sol-gel [19], molten saltroute [20], ultrasonic radiation [21], tartrate precursor [22], electrodeposition [23], urea combustion [24], aerogel [25], mechanochemical [26], etc. have been developed to synthesize nanosized zinc ferrites.…”

Room temperature magnetism in zinc nano ferrite synthesized by a novel oxalate-ceramic method

“…The zinc ferrite in nanocrystalline form has been studied recently by many researchers [3e7]. Hamdeh et al found that inversion takes place in zinc ferrite at low temperature when synthesized in nanocrystalline size [3]. Ammar et al [4] observed ferrimagnetic behavior at low temperature and observed the size dependent canting in zinc nano-ferrite [4].…”