Anomalous alternating current magnetoresistance in La0.5Ca0.5Mn1-xNixO3 (x=0.04)

作者：Barik S K; Mahendiran R^*

来源：Journal of Applied Physics, 2011, 109(7): 07D724.

DOI：10.1063/1.3556758

We report the magnetic field and temperature dependences of ac electrical transport in La0.5Ca0.5 Mn0.96Ni0.04O3 as a function of frequency. The ac magnetoresistance shows an anomalous behavior as a function of field: it is negative and exhibits a bell shaped curve about the origin (H = 0 T) at f = 0.1 MHz, but it transforms into a valley at the origin (accompanied by a positive peak on either side of the origin) for f >= 3 MHz at T = 125 K. With increasing frequency, the depth of the valley increases and the position of the peak shifts toward higher field. However, the magnetoreactance is negative and exhibits only a single peak at the origin for all temperatures and frequencies. At T = 125 K and f = 5 MHz, a magnetoresistance of vertical bar 80% and a magnetoreactance of similar to 90% were found for H = 2 T. These results are very different from those for La0.7Sr0.3MnO3, and we discuss the possible origins of the observed anomalous ac magnetotransport in this compound.

• 出版日期2011-4-1