The solid solution NiFe_2-xMn_xO₄ (0 ≤ x ≤ 2) is synthesized by sol gel method and the physical properties are investigated for the first time. The thermal analysis shows that the phases are formed above 400 °C. The oxides crystallize in an inverse cubic spinel whose lattice constant (a: 0.83381–0.83985 nm) increases only slightly up to x = 1.6, according to the Vegard’s law; such result is supported by the FTIR spectra. The UV-Visible spectroscopy shows both direct (1.00–1.56 eV) and indirect optical transitions (0.39–1.65 eV) due to the crystal field splitting of 3d metal. Field-dependent magnetization of the solid solution was measured at 300 K in the region (±20 kOe) and the end member NiFe₂O₄ exhibits a high magnetism with a saturation magnetization (20 emu/g), comparable to that reported previously. The saturation magnetization varies between 0.5 and 20 emu/g while the coactivity fluctuates between 110 and 239 Oe. The thermal variation of the electrical conductivity indicates a conduction mechanism by low polaron hopping which follows an exponential law with variable activation energies (E_a: 0.12–033 eV). The thermo-power is positive and nearly constant (S_300K: 144–130 µVK⁻¹), indicating p type conduction with a mobility more a less constant (1.5–8 × 10⁻⁶ V² cm⁻¹ s⁻¹). The hole densities (N_A × 10¹⁶: 0.26–2.17) are determined electrochemically from the capacitances measurements in neutral medium (Na₂SO₄ 0.5 M). The flat band potential (E_fb: −0.04 to −0.29 V) does not change significantly indicating that the valence band derives mostly from 3d orbital.

通过溶胶凝胶法合成固溶体NiFe _2-x Mn _x O ₄（0≤x≤2），并首次研究其物理性质。热分析表明，相在400°C以上形成。氧化物在逆立方尖晶石中结晶，根据维加德定律，其晶格常数（a：0.83381–0.83985 nm）仅略微增加到x = 1.6。FTIR光谱支持这种结果。由于3d金属的晶体场分裂，紫外可见光谱显示直接（1.00-1.56 eV）和间接光学跃迁（0.39-1.65 eV）。在300 K的区域（±20 kOe）和端部件NiFe _2中测量了固溶体的场相关磁化强度O ₄具有高磁化强度，饱和磁化强度（20 emu / g），与以前报道的相当。饱和磁化强度在0.5和20 emu / g之间变化，而共活性在110和239 Oe之间波动。电导率的热变化表明低极化子跳跃是一种传导机制，其遵循具有可变激活能（E _a：0.12-033 eV）的指数定律。热功率为正且接近恒定（S _300K：144–130 µVK ^-1），表明p型导电性随迁移率的变化而变得较小（1.5–8×10 ^-6 V ² cm ^-1 s ^-1）。孔密度（N_A  ×10 ¹⁶：0.26-2.17）由中性介质（Na ₂ SO ₄ 0.5 M）中的电容测量电化学确定。平坦带电势（E _fb：-0.04至-0.29 V）没有明显变化，表明价带主要来自3d轨道。