Room temperature ferromagnetism in Co-doped La0.5Sr0.5TiO3−δ nanoparticles

Abstract

The authors report room temperature ferromagnetism in La0.5Sr0.5Ti0.985Co0.015O3−δ nanoparticles with particle sizes of ∼12–14nm. Nanoparticles of undoped and Co-doped samples were synthesized by a polymerized complex method and were characterized using x-ray diffraction and transmission electron microscopy. The magnetic properties of the nanoparticles were determined using vibrating sample magnetometry. The undoped samples exhibit a diamagnetic behavior, whereas all the Co-doped samples are ferromagnetic having the specific magnetizations of ∼0.011–0.038emu∕g at 10kOe. The finding of room temperature ferromagnetism in the Co-doped samples would allow an enhanced flexibility for applications.

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

“…The saturated magnetization (Ms) increases as annealing temperature decreases, and attains the peak value (Ms =0.11 emu/g) at 973 K, then it decreases when the annealing temperature decreases. 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.…”

“…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.…”

“…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.…”

“…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.…”

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

“…In a study of perovskite oxides with a general formula of La 0.4 Sr 0.6 Ti 1Àx Mn x O 3Àd (x = 0, 0.2, 0.4 and 0.6), Fu et al [3] reported that the materials were thermally and chemically compatible with yttria-stabilized zirconia and could be used as anodes in electrolyte-supported cells. In addition, Wongsaprom et al [4] demonstrated the existence of ferromagnetism in Co-La 0.5 Sr 0.5 TiO 3 and they indicated that the undoped samples were diamagnetic, whereas the Co-doped sample showed ferromagnetism at room temperature.…”