Magnetic field at Ce impurities in La sites of La0.5Ba0.5MnO3 double perovskites

B Bosch-Santos,N M Nascimento,A W Carbonari,M Saiki,G A Cabrera-Pasca,T S N Sales,E L Correa,L F D Pereira,J Schell,R N Saxena

doi:10.1063/1.5080094

Abstract

Due to its rich variety of electromagnetic properties, such as a colossal magnetoresistance, charge and orbital ordering, and metal-insulator transition, the magnetic behavior in La0.5Ba0.5MnO3 double perovskite compounds has been investigated by several techniques, however more experimental data, especially from atomic resolution techniques, are still necessary to understand such complex behavior. In this paper, we have used a nuclear and short-range technique, the Perturbed Angular Correlation (PAC) spectroscopy, to investigate the magnetic hyperfine interaction at the 140Ce and 111Cd probe nuclei as impurities occupying La sites. This double perovskite samples were synthesized by Sol-Gel route. The crystal structure was determined by X-ray diffraction and the analyses showed that this method produced perovskite oxides with cubic structure in Pm-3m space group and the homogeneity was determined by Transmission Electron Microscopy (TEM). The local properties investigated by PAC spectroscopy revealed a ferromagnetic transition temperature above 300 K and a pure antiferromagnetic interaction below 100 K. Moreover, it also indicates an anomalous behavior of the temperature dependence of magnetic hyperfine field at La sites measured with 140Ce probe nuclei, which can be ascribed to the contribution of 4f band of Ce to Magnetic Hyperfine Field (Bhf) at low temperatures due to the increase in its localized character.

Highlights

The series of cobaltite and manganite double oxide perovskites present a large variety of physical behaviors
The crystal structure was determined by X-ray diffraction and the analyses showed that this method produced perovskite oxides with cubic structure in Pm-3m space group and the homogeneity was determined by Transmission Electron Microscopy (TEM)
It indicates an anomalous behavior of the temperature dependence of magnetic hyperfine field at La sites measured with 140Ce probe nuclei, which can be ascribed to the contribution of 4f band of Ce to Magnetic Hyperfine Field (Bhf) at low temperatures due to the increase in its localized character

Summary

Introduction

The series of cobaltite and manganite double oxide perovskites present a large variety of physical behaviors. The family of double perovskites LaBaTM2-δO6-δ (TM = Mn, Co) showing multi-magnetic transitions, such as paramagnetic to ferromagnetic and to antiferromagnetic, have been investigated intensively in the last decades because these compounds present a rich variety of interesting properties, colossal magnetoresistance, charge and orbital ordering, and metal-insulator transition.. The family of double perovskites LaBaTM2-δO6-δ (TM = Mn, Co) showing multi-magnetic transitions, such as paramagnetic to ferromagnetic and to antiferromagnetic, have been investigated intensively in the last decades because these compounds present a rich variety of interesting properties, colossal magnetoresistance, charge and orbital ordering, and metal-insulator transition.3,4 Due to these properties, these compounds are good candidates for important technological applications such as oxidation catalysts, gas sensors and electron conduction devices..

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