Particle size effects on stripe ordering and magnetic properties in nanosized La5/3Sr1/3NiO4

The structural, magnetic and transport properties of stripe ordered La5/3Sr1/3NiO4 nanoparticles synthesized by the sol-gel method were investigated. Compared with the bulk sample, it is found that the charge order is weakened in the nanosized particles. Accompanied by the disappearance of the antiferromagnetic spin-ordered state, a ferromagnetic-like phase emerges at ∼23 K. Furthermore, the spin glass/spin reorientation transition temperature TCA for the ∼100 nm particles is ∼65 K which is ∼12 K higher than that of the bulk. This suggests that instead of the stabilization of charge order, the structural disorder may have a dramatic effect on the complex magnetic transition in the stripe phase systems.