Structural and magnetic properties of CaMg2Fe16O27

Abstract

A new compound, CaMg 2 Fe 16 O 27 , is synthesized for the first time, in polycrystalline form, using stoichiometric mixture of oxides with standard ceramic technique and characterized by X-ray diffraction. It is found to have a hexagonal W-type structure with lattice parameters a = 5⋅ ⋅850 Å and c = 33⋅ ⋅156 Å. Electrical studies show that the compound is a semiconductor with energy of activation, ∆ ∆E = 0⋅ ⋅56 eV. Electrical conductivity results show a transition in the conductivity vs temperature plot near the Curie temperature. The activation energy value obtained for the paramagnetic phase is found to be higher than that of the ferrimagnetic phase. The molar magnetic susceptibility was measured in the temperature range 300-850 K and the results show that the compound is ferrimagnetic at room temperature. The compound also shows hysteresis at 300 K. Paramagnetic nature of the sample above Curie temperature is also studied. The Curie molar constant C M calculated from the plot of 1/χ χ M vs T(K) is found to be nearly in agreement with the expected value.

Enhancement of electrical and dielectric properties of Cr doped BaZn2 W-type hexaferrite for potential applications in high frequency devices

“…The activa- The room temperature resistivity ( RT ) experiences a significant increase from a value of 3.25 × 10 8 cm to 2.79 × 10 9 cm with an increase in Cr concentration. The room temperature resistivity of W-type hexaferrites measured by various researchers is found to be in the range of 10 4 -10 7 cm [13,31]. However, in the present work, the resistivity of the Cr doped samples has been increased up to a value of ∼10 9 cm.…”

Magnetic and dielectric behaviors of Ba0.2Sr0.8Co0.8Fe0.2O3-δ oxide

“…Hence, conduction may take place through multiple-level hoping [9]. The dip observed around temperature $700 K is in the vicinity of the ferromagnetic transition temperature and it is attributed to the change in spin arrangement in the compound at the ferromagnetic transition temperature below which magnetic ordering sets in [10]. In the temperature 373-523 K region conductivity is almost temperature independent and it varies with frequency.…”

Effect of Europium Concentration on the Physical Properties of Ni-Zn Ferrite Substituted by Mn2+ Ion.

“…This decrease of resistivity in ferrite is due to the exponential increase of drift mobility of charge carriers with temperature. The DC resistivity of the studied ferrite was studied in the light of the formula [11].…”