Evidence of short-range magnetic ordering above TC in the double perovskite La2NiMnO6

The magnetic properties of the double perovskite La2NiMnO6 polycrystalline sample have been investigated by magnetometry and electron spin resonance. The magnetization curve shows a paramagnetic-ferromagnetic transition at TC∼280K. However, the electron spin resonance spectra reveal that a pure paramagnetic regime only exists above T*∼390K in which the behaviors of the spectra can be well described by the small polaron hopping model. Between TC and T*, a short-range magnetic ordering appears which maybe derives from the correlation of those magnetic polarons. The possible relationship between those polarons and the observed multifunctions in La2NiMnO6 is briefly discussed.