Alternating current magnetotransport in Sm0.1La0.6Sr0.3MnO3

M Aparnadevi,R Mahendiran

doi:10.1063/1.4789408

Abstract

We report frequency dependent (f = 0.1 to 5 MHz) electrical resistivity in Sm0.1La0.6Sr0.3MnO3 in superimposed dc magnetic fields (H = 0–1 kOe). Resistive (ρ′) and reactive (ρ″) components of the complex resistivity (ρ = ρ′+iρ″) were measured simultaneously. With increasing f, both ρ′ and ρ′′ increase abruptly at the onset of ferromagnetic transition (Tc = 348 K) and exhibit an anomaly at T *≈ 147 K ≪ Tc in H = 0 kOe. The observed features in ρ′ and ρ′′ are depressed with increasing H leading to 35% magnetoresistance for ΔH = 300 Oe and f = 3 MHz. It is suggested that the frequency dependent magnetotransport is dominated by the field and frequency dependences of the ac permeability.

Highlights

Since the discovery of colossal magnetoresistance in perovskite manganites nearly two decades ago, numerous investigations have focused on electrical resistivity and magnetoresistance measured with direct current.[1]
An interesting question is what happens to the electrical resistivity and magnetoresistance if the charge carriers are subjected to an alternating current
Electrical response of insulating manganites (RMnO3 where R = Tb, Gd, Dy, and Bi) to alternating electrical field in kHz frequency range (f = 1–10 kHz) in presence of magnetic field is a topic of current interest due to coupling between magnetic and electrical dipoles that leads to magnetically tunable capacitance or electrical polarization in some manganites.[3,4]

Summary

INTRODUCTION

Since the discovery of colossal magnetoresistance in perovskite manganites (example. La0.7Sr0.3MnO3) nearly two decades ago, numerous investigations have focused on electrical resistivity and magnetoresistance measured with direct current (dc).[1]. The purpose of this letter is to investigate radiofrequency (rf) electrical transport in a La substituted Sm0.7Sr0.3MnO3 sample both as a function of temperature and magnetic field. We were partly motivated by our earlier observation of unusual double magnetic phase transitions in Sm0.6-xLaxSr0.4MnO3 series.[11] The field–cooled magnetization of compounds in this series, with the exception of the end member (x = 0.6), showed anomalous decrease of magnetization below a temperature T ∗ within the long-range ferromagnetic state. Ordering of Sm moment in the parent antiferromagnetic SmMnO3 causes negative magnetization below the compensation point Tcomp = 9.4 K.12,13. Ac magnetotransport in these compounds has not been reported so far

EXPERIMENT DETAILS

RESULTS

Findings

SUMMARY