Issue 46, 2016

Observation of room temperature magnetodielectric effect in Mn-doped lanthanum gallate and study of its magnetic properties

Abstract

Polycrystalline samples of Mn-doped LaGa1−xMnxO3 (LGMO) with 0 ≤ x ≤ 0.2 have been prepared via solid-state reaction method. The structural phase purity of all these samples was confirmed by powder X-ray diffraction experiments carried out at the BL-12 beamline of the Indus-2 synchrotron radiation source. Room-temperature (RT) dielectric measurements were performed in the absence and presence of a magnetic field. A noticeable magnetodielectric (MD) effect, i.e., a change in the value of the dielectric constant owing to the application of a low magnetic field, was observed in the LGMO sample with x = 0.2 (LG8M2O). In order to separate the intrinsic and resistive contributions present in the observed RT MD effect, magnetoresistance impedance spectroscopy (MRIS) was performed at RT. The present MRIS analysis suggests that at frequencies corresponding to the grain contribution (≥105 Hz for the present samples), the observed MD phenomenon appears to be an intrinsic property of the presently studied samples, whereas at lower probing frequencies (<105 Hz) the observed change appears to be dominated by MR (considering frequency-dependent resistance), which was possibly due to the coexistence of Mn3+ and Mn4+. The coexistence of Mn3+ and Mn4+ was revealed by XANES (Mn K-edge) spectroscopy. Moreover, RT and low-temperature magnetization–magnetic field (MH) measurements, along with MT measurements in FC and ZFC modes, were performed to investigate the state of magnetic ordering. The appearance of a narrow MH loop indicates the presence of some magnetic ordering at RT. Furthermore, a ferromagnetic (FM) transition observed around 36 K and a normal MH loop with saturated magnetization recorded at 5 K confirm FM ordering at low temperatures, whereas a bifurcation in FC-ZFC curves indicates competing FM and antiferromagnetic (AFM) interactions at low temperatures.

Graphical abstract: Observation of room temperature magnetodielectric effect in Mn-doped lanthanum gallate and study of its magnetic properties

Supplementary files

Article information

Article type
Paper
Submitted
23 Aug 2016
Accepted
24 Oct 2016
First published
26 Oct 2016

J. Mater. Chem. C, 2016,4, 10876-10886

Observation of room temperature magnetodielectric effect in Mn-doped lanthanum gallate and study of its magnetic properties

H. M. Rai, S. K. Saxena, V. Mishra, A. Sagdeo, P. Rajput, R. Kumar and P. R. Sagdeo, J. Mater. Chem. C, 2016, 4, 10876 DOI: 10.1039/C6TC03641D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements