Structural and multiferroic properties of BiFeO3/MgLa0.025Fe1.975O4 nanocomposite synthesized by sol–gel auto combustion route

Abstract

Nanocomposites of (1−x)BiFeO3(BFO)–xMgLa0.025Fe1.975O4(MLFO) (x = 0.0, 0.1, 0.2, 0.3 and 1.0) for enhanced multiferroic properties have been synthesized via sol–gel auto combustion route. Results of X-ray diffraction pattern, Field emission scanning electron microscopy and energy dispersive spectroscopy revealed the formation of composites and phase analysis for all the samples. Room temperature magnetic measurements (M–H curve) through vibrating sample magnetometer evidenced increasing trend in saturation magnetization (MS) from 0.23 to 5.28 emu/g for x = 0.0 to 0.3 samples, while smaller than MS value (17.06 emu/g) of MLFO nanoparticles. Antiferromagnetic transition or Neel temperature (TN1) for x = 0.0 and x = 0.3 samples were recorded by M–T plot (magnetization vs. temperature curve) and found to be 360 °C and 348 °C, respectively. Room temperature dielectric constant (er) and dielectric loss (tanδ) in the frequency range 100 Hz to 2 MHz were studied for x = 0.0 to 0.3 samples. Temperature-dependent dielectric constant for all the samples exhibited an anomaly near to the antiferromagnetic transition temperature of BFO. Improved ferroelectric property has been observed by virtue of enhancement in the polarization of composite samples. Electric field-guided strain as a function of the applied electric field has shown asymmetric behaviour for pristine BFO and symmetric loop has been observed for all the composite samples with increasing trend in highest peak-to-peak strain value (SP = 0.06 to 0.53% for x = 0.0 to 0.2 and 0.07 for x = 0.3) which makes these materials active for magnetoelectric devices.