Experimental evidence of coupling interaction between charge ordering and spin ordering

Abstract

In order to experimentally probe into the complicated interaction between charge ordering and spin ordering in manganites, two sets of samples Nd 0.5 Sr 0.5 Mn 1−x Ga x O 3 (NSMGO) and Nd 0.5 Sr 0.5 Mn 1−y Cr y O 3 (NSMCO) (0.0 x, y 0.075), have been studied by means of electrical transport, magnetization, electron spin resonance and transmission electron microscopy analysis. By comparing the influence of Cr-doping and Ga-doping in the Nd 0.5 Sr 0.5 MnO 3 (NSMO) system, large difference between the evolution of charge ordering temperature T co in the Cr-doping and the Ga-doping cases is found. In the NSMCO system, the CE-type antiferromagnetic (AFM)/charge ordering (CO) phase disappears with only 2.5 percent Cr doping; but in the NSMGO system, the CE-type AFM/CO phase always exists. This phenomenon indicates that the charge ordering formation is dominated by the spin ordering. As a result, it is experimentally proved that there is strong coupling interaction between charge ordering and spin ordering in NSMO system. perovskite manganites, phase transitions, order-disorder effects PACS: 75.47.Lx, 74.25.Ha,