Weak Ferromagnetic Property and Electromagnetic Waves Absorption Characteristic of La(1-x)BaxMnO3

Andon Insani,Engkir Sukirman,Yose Fachmi Buys,Yosef Sarwanto,Wisnu Ari Adi

doi:10.26776/ijemm.04.03.2019.02

Abstract

The weak ferromagnetic property and the electromagnetic waves absorption characteristic of La(1-x)BaxMnO3 (LBMO) compounds have been investigated. The samples of LBMO that are LaMnO3 (S0), La0.9Ba0.1MnO3 (S1); La0.8Ba0.2MnO3 (S2); and La0.7Ba0.3MnO3 (S3) were synthesized using high energy milling (HEM) method. Samples were characterized by means of XRD (X-ray diffractometer), HRPD (high-resolution powder neutron diffractometer), EDS (energy dispersive X-ray spectroscopy, VSM (vibrating sample magnetometer), and VNA (vector network analyzer). There is no magnetic ordering of ferromagnetic in S1 and S2 samples due to the Ba occupation factors of both less than 0.2. The Ba content in the S3 sample is greater than 0.2, hence the ferromagnetic property of the compound is not so visible with the VSM as well as the VNA. The absorption characteristics of electromagnetic waves using VNA indicated that there is an absorption of EM waves in the frequency range between 8-12 GHz with almost the same peak frequency for all four samples at 10.8 GHz with the absorption of around 5 dB. The existence of a weak ferromagnetic property can be detected clearly using HRPD. Neutron diffraction as a probe can observe the magnetic structure accurately even in a material having a weak ferromagnetic property.

Highlights

The parent compound, LaMnO3 with perovskite ABO3 structure has antiferromagnetic insulator properties in which Mn is present in a single oxidation state (Mn+3)
3 RESULTS AND DISCUSSIONS The Rietveld analysis based on the X-ray diffraction data using general structure analysis system (GSAS) software from the LaMnO3, La0.9Ba0.1MnO3, La0.8Ba0.2MnO3, and La0.7Ba0.3MnO3
According to previous research [11], the S0 sample should display the properties as a paramagnetic material. This will be proved by measurement using vibrating sample magnetometer (VSM)

Summary

Introduction

The parent compound, LaMnO3 with perovskite ABO3 structure has antiferromagnetic insulator properties in which Mn is present in a single oxidation state (Mn+3). The conductivity of rare-earth manganese oxides is enhanced to approach that of metal or semiconductor from the insulating state when doped and their colossal magnetoresistance effect (CMR) is remarkable [2]. They are fascinating to be studied and applied on a large scale due to their unusual electromagnetic properties [3−5]. Substitutions at the trivalent rare earth site (A-site) by a divalent alkaline earth metal ion like Ca, Sr, Ba or Pb causes part of the Mn+3 are oxidized to Mn+4 ions and transforms this compound to a ferromagnetic metal [9]. The ferromagnetic behaviour occurred due to magnetic interactions between Mn3+ and Mn4+ ions through the doubleexchange mechanism [10]

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