Study on the field-cooling induced magnetic interactions in Gd-doped NiO nanoparticles
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Date
2020-01-01
Journal Title
Journal ISSN
Volume Title
Publisher
ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS
Abstract
We herein investigate the novel magnetic interactions, such as exchange bias (EB), memory effect (ME) and magnetic relaxation dynamics (MRD) in NiO and 10 wt% Gd doped NiO nanoparticles synthesized by hydrothermal process. X-ray diffraction studies showed crystallization of face-centered-cubic structure for both NiO and Gd-doped NiO nanoparticles. Transmission electron microscopy analysis revealed a spherical morphology for both samples and their mean particle sizes were estimated as 24.5 and 10.3 nm for the pure and Gd-doped NiO nanoparticles, respectively. SQUID magnetic measurements demonstrated the occurrence of large EB coupling: 1.04 and 0.767 kOe; and enhanced coercive fields: 1.75 and 1.27 kOe, for the pure and Gd-doped NiO nanoparticles, respectively. The size-dependent magnetic properties such as, EB, ME and MRD is found to vanish at the average blocking temperature and interestingly, these properties set-in on cooling the samples at 5 K under applied field of 5 kOe. The surface defects such as oxygen vacancies and the Gd2O3 impurity phase played a significant role in determining the EB and ME characteristics of NiO nanoparticles.
Description
Subject(s)
Nickel oxide, NiO, Superparamagnetism, Exchange bias, Memory effect