Magnetic and structural properties of La3Ni2SbO9

FRANCO D. G.; CARBONIO R. E.; NIEVA G.

Valparaíso, Chile

Congreso; Sólidos 2009; 2009

A large variety of physical properties have been observed in perovskites, wich are oxides with general formula ABO3. Substitution at the B site cation gives rise to compounds of the type AB1-xB’xO3, where B and B’ can be located at two different octahedral sites, 2c and 2d. These compounds are called double-perovskites. We have synthesised the double perovskite La3Ni2SbO9 (La2(Ni)2c(Ni1/3Sb2/3)2dO6). A structural analysis of the XR diffraction pattern indicates that the crystalline symmetry is that of the spatial group P21/n. Two different crystallographic sites for Ni2+ and Sb5+ were found, the order among those cations being almost the maximum possible for this compound stoichiometry. Magnetization M vs. Temperature T (2K-350K) and Field (up to 1T) measurements were performed in a QD magnetometer. M vs. T curves indicate a paramagnetic behaviour of  Ni2+down to Tc=176K, where the system undergoes a ferromagnetic transition.  Figure 1 shows a typical low temperature hysteresis loop. The same qualitative behaviour is observed at 2, 5, 10 and 15 K. The initial branch of the curves lies outside the hysteresis loop (see figure 1).  This behaviour was found in nanoparticles[1] where strong surface anisotropy was detected.  Above 15K this feature disappears.