We report our investigations on the magnetic, thermal, optical and dielectric properties of the nanocrystalline La_0.7Sm_0.3Cr_1−xFe_xO₃ (0 ≤ x ≤ 0.3) samples synthesized through sol–gel auto-combustion process. The maximum magnetization and coercive field increase in Fe-doped samples. Fourier transform infrared (FTIR) spectra reveal the metal–oxygen (Cr/Fe–O) stretching and bending modes of vibration. Thermal analysis illustrates the occurrence of structural phase transition at ~ 290 °C for the pristine sample, and the phase transition temperature rises with the increase in Fe concentration. The specific heat capacity at constant pressure also reflects this transition. The energy band gap reduces for the doped samples. Dielectric constant, dielectric loss and loss tangent exhibit the usual frequency dependence and decrease with the amount of Fe. The Giuntini law implies higher contribution of polaronic conduction in the doped samples. Electric modulus analysis also shows the manifestation of both short- and long-range-order conduction processes in this system. The Nyquist plots for both impedance and electric modulus emphasize that grains dominate the conduction process. Temperature-dependent impedance and electric modulus analysis established that the relaxation processes are thermally activated and deviate from the ideal Debye behaviour.

我们在纳米晶体的La的磁，热学，光学和介电性能报告我们的调查_0.7钐_0.3铬_{1- X}的Fe _X ø ₃（0≤  X ≤0.3）通过溶胶-凝胶自动燃烧过程合成的样品。掺铁样品的最大磁化强度和矫顽场增加。傅立叶变换红外（FTIR）光谱揭示了金属-氧气（Cr / Fe-O）的拉伸和弯曲振动模式。热分析表明，原始样品在约290°C时发生结构相变，并且相转变温度随Fe浓度的增加而升高。恒定压力下的比热容也反映了这种转变。对于掺杂样品，能带隙减小。介电常数，介电损耗和损耗角正切表现出通常的频率依赖性，并且随Fe的含量而降低。该Giuntini规律表明掺杂样品中极化波传导的贡献更大。电模量分析还显示了该系统中短程和长程传导过程的表现。阻抗和电模量的Nyquist图强调了晶粒占主导地位的导电过程。温度相关的阻抗和电模量分析确定了松弛过程是热激活的，并且偏离了理想的德拜行为。