Influence of length and measurement geometry on magnetoimpedance in La0.7Sr0.3MnO3

TL;DR

This study investigates how the length and measurement geometry affect the magnetoimpedance in La0.7Sr0.3MnO3, revealing high-frequency transport sensitivity to local magnetic permeability variations.

Contribution

It demonstrates the influence of measurement geometry on ac magnetoresistance and reactance in La0.7Sr0.3MnO3, highlighting the importance of local magnetic properties at high frequencies.

Findings

Ac magnetoresistance reaches 47% at room temperature.

Magnetoreactance exhibits a double peak behavior.

Measurement geometry significantly affects ac magnetoresistance and reactance.

Abstract

We show that ac magnetoresistance at room temperature in La0.7Sr0.3MnO3 is extremely high (= 47% in H = 100 mT, f = 3-5 MHz), and magnetic field dependence of reactance exhibits a double peak behavior. However, magnitudes of the ac magnetoresistance and magnetoreactance for a fixed length of the sample (li) decrease with decreasing separation (lv) between voltage probes unlike the dc magnetoresistance. On the contrary, change in li has a negligible influence on magnetoimpedance when lv is fixed. Our results indicate that high frequency electrical transport is sensitive to local variations in the magnetic permeability.