Fe-doped La0.5Sr0.5TiO3−δ nanoparticles: A diluted magnetic oxide system

Abstract

We report room-temperature ferromagnetism in ∼11.4–14.6nm nanoparticles of La0.5Sr0.5Ti0.985Fe0.015O3−δ. Nanoparticles of undoped and Fe-doped samples were synthesized by a polymerized complex method and were characterized using x-ray diffraction, transmission electron microscopy, and vibrating-sample magnetometer. The undoped samples exhibit a diamagnetic behavior, whereas the Fe-doped samples are ferromagnetic having the specific magnetizations of 0.041–0.101emu∕g at 10kOe. Our results indicate that the ferromagnetic property of La0.5Sr0.5Ti0.985Fe0.015O3−δ system is intrinsic and is not a result of any secondary magnetic phase or cluster formation. The finding of room-temperature ferromagnetism in this system would stimulate further interest in the area of diluted magnetic oxides.

Effect of annealing conditions on the magnetism of Ni-doped La0.4Sr0.6TiO3−δ powders

“…Except Ni, the peaks of Ti, Sr, and La were observed. The Cu and C came from a copper grid and carbon contamination [13,14]. Our results indicate that using the sol-gel method, part of Ti ions was successfully substituted by Ni ions in the Ni-LSTO structure.…”

“…These phenomena have been observed in Co-LSTO [13]. But in Fe-LSTO particles [14], the Ms values increase monotonously with increase of annealing temperature. The peak values of Ms in Fe-LSTO and Co-LSTO are 0.101 emu/g calcined at 1203 K and 0.038 emu/g calcined at 1073 K, respectively.…”

“…More recently, RTFM has also been reported in perovskite of Co-doped (La,Sr)TiO 3 À d nanoparticles and thin films [13][14][15][16][17]. Wongsaprom et al [13] reported the existence of ferromagnetism in Co-doped La 0.5 Sr 0.5 TiO 3 À d fabricated by a polymerized complex (PC) method.…”

“…The specific saturation magnetization (Ms) value of 0.038 emu/g was observed for the sample calcined at 1073 K which provides strong indication that Co-doped La 0.5 Sr 0.5 TiO 3 À d nanoparticles display RTFM. In Fe-doped La 0.5 Sr 0.5 TiO 3 À d system, the undoped samples are diamagnetic, whereas the Fe-doped samples show ferromagnetism at room temperature [14]. In virtue of tunneling magnetoresistance (TMR) experiments Herranz et al [18] demonstrate the existence of a significant spin polarization in Co-doped (La, Sr)TiO 3 À d , a ferromagnetic diluted magnetic oxide system with high Curie temperature by using low-oxygen pressure growth conditions.…”

La0.5Sr0.5TiO3 nanopowders prepared by the hydrothermal method

“…Generally, the multicomponent oxide systems, i.e., (Pb,Sr)TiO 3 , (Ba,Ca)TiO 3 , (Pb,La)TiO 3 and (La,Sr)TiO 3 perovskites, are usually fabricated by a conventional solid state reaction [5], thermal decomposition [6], molten salt [7], polymerized complex [8], coprecipitation [9], and sol-gel [10]. Alternatively, a more attractive method is the hydrothermal method, due to the simplicity of its preparation process at low temperature, without high temperature calcination.…”