Estimating the cation distributions in the spinel ferrites Cu0.5−xNi0.5ZnxFe2O4 (0.0≤x≤0.5)

Influence of Zn2+ doping on the structural and surface morphological properties of nanocrystalline Ni-Cu spinel ferrite

“…Many methods such as sol-gel auto-combustion technique [16], chemical coprecipitation [17], citrate precursor method [18], oxalate precursor technique [19], and ceramic method [20] are used to prepare Ni-Cu-Zn spinel ferrite. Among them, the sol-gel auto-combustion method has unique advantages such as excellent composition control, low temperature process, low production cost, and better results.…”

Quantum mechanical method for estimating ionicity of spinel ferrites

“…In the quantum mechanical model to estimate the cation distribution [13][14][15][16], we assume that there is a square potential barrier between a cation-anion pair. The height of the potential barrier is proportional to the ionization energy of the last ionized electron, and the width of the potential barrier is related to the distance between neighboring cations and anions.…”

“…In earlier works [13][14][15][16], we proposed a quantum-mechanical method for estimating the cation distribution in cubic spinel ferrites, where materials were treated as ionic compounds without covalent bonds. In this paper, using both magnetization and density of states calculated by the density functional theory, ionicity of cubic spinel ferrite Fe 3 O 4 is determined.…”

“…Furthermore, a quantum mechanical method for ionicity of spinel ferrites was proposed by comparing the Phillips' ionicity data [1]. On the basis of this, we improved the quantum-mechanical method for estimating the cation distribution in cubic spinel ferrites [13][14][15][16], and re-calculated the cation distribution of the spinel ferrites MFe 2 O 4 (M¼ Fe, Co, Ni, Cu). We believe that our treatment method about cation distribution of spinel ferrites with ionicity will also be beneficial for magneto-optical and dielectric investigations of spinel ferrite.…”

Magnetic moments of Ti cations in Ti-doped Ni0.68Fe2.32O4 spinel ferrites

“…These behaviors suggest following properties of the samples: (i) The Ti cations in the samples have magnetic moments. If the Ti cations were in the Ti 4+ state without magnetic moment, there should not be a transition temperature T N , in which case, the r -T curves should decrease monotonically with increasing measurement temperature, being similar to those of Zn doped samples (the Zn 2+ cation has no magnetic moment) [15]. (ii) The magnetic moments of the Ti cations are close to antiparallel to those of the Fe and Ni cations at 10 K. (iii) When T > 10 K, r and dr/dT both start to increase, indicating that a canting angle of the magnetic moments between Ti cations and Fe (Ni) cations appears and increases with increasing measurement temperature.…”