Investigation of magnetic interactions, electrical and magneto-transport properties in Ga-substituted La_(0.4)Bi_(0.6)MnO_3 perovskite manganites

摘要

We report on magnetic, electrical and magneto-transport properties in La_(0.4)Bi_(0.6)Mn_(1－x)Ga_xO_3 (with x = 0.05 and x = 0.1) samples. The phase purity and microstructural analysis of the samples have been carried out using X-ray diffraction and scanning electron microscopy technique. From the magnetization data, the studied samples show paramagnetic to ferromagnetic transition followed with glassy behavior at low temperatures. Frequency dependent ac susceptibility measurements reveal dynamic fluctuations due to cooperative interactions between antiferromagnetic domain pinning effects giving rise to glassy behavior in the studied samples. Electrical resistivity measurements suggest semiconducting behavior for the studied samples in the measured temperature range (100-300 K). Our study reveals that resistivity data for T≤ (θ_D/2, the Debye temperature) follow power law and for T＞θ_D/2 Shklovskii-Efros variable range hopping transport mechanism. The MR% vs. magnetic field has been studied to understand the simultaneous behavior of FM and insulating nature around T= 100 K existing in the samples.