Synthesis, structural, electrical and magnetic properties of Bi2Fe4-xGaxO9 (0 ≤ x ≤ 1.6)

We investigate the electrical and magnetic properties of the Bi2Fe4-xGaxO9 (0 ≤ x ≤ 1.6) polycrystalline samples synthesized via solid-state reaction technique. Magnetic susceptibility measurements reveal that lightly doped samples (x < 0.8) undergo successive transitions, from high-temperature paramagnetic to antiferromagnetic phase followed by a low-temperature spin-glass state while the samples with heavy doping (x > 0.8) demonstrate paramagnetic to spin-glass (SG) transition. The variation of irreversible temperature obtained from zero field cooling (ZFC) and field cooling (FC) susceptibilities versus measured magnetic field and low-temperature magnetic hysteresis (M-H) loops support the existence of spin-glass phase. The dielectric constant (Ɛr) of Bi2Fe4-xGaxO9 with Ga-dilution reveals a weak-temperature sensitivity in high-temperature range (300 K ≤ T ≤ 550 K), which is advantageous for high temperature capacitor applications and electronic devices.