2009/02/10 by A. Rebello, C. L. Tan, Can Tan +4
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic Properties of Alloys #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Rare-earth and actinide compounds #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.0902.1780
20 pages, 7 figures
arxiv created 2009/02/10 · openalex publication_date 2009/02/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report ac electrical transport in La0.7Sr0.3CoO3 and La1-xSrxMnO3 (x = 0.18- 0.5) as a function of temperature and frequency in H = 0 and 60 mT. Both resistive (R) and reactive (X) components of impedance (Z = R+jX) were measured. It is shown that a smooth decrease of the resistance around the Curie temperautre in La0.7Sr0.3CoO3 transforms into an abrupt increase followed closely by a peak in R with increasing frequency. Similar behavior in R was also found in metallic compositions of the La-Sr-MnO3 series. The observed anomaly at TC is suppressed by a small dc magnetic field of H = 60 mT which rrsults in a huge ac magnetoreistance (= 30 % in manganite and =7 % in cobaltite at f = 2 MHz). The anomaly in R in zero field is also accompanied by a sudden incrases of X. While the ac magnetoresitance is negative as a function of field from 100 Hz to 30 MHz, we show that the sign of X changes and a new double peak structure develops in X for frequencies above 15 MHz.