High Temperature Spin-glass-like Transition in La0.57Sr0.33MnO3 Nanofibers near the Curie Point

Document Type

Article

Publication Date

6-16-2017

Publication Title

Physical Chemistry Chemical Physics

Abstract

The glassy transition of superparamagnetic (SPM) (r < r0) nanoparticle systems usually occurs at a very low temperature that greatly limits its application to high temperatures. In this work, we report a spin-glass-like (SGL) behavior near the Curie point (TC), i.e., T0 = 330 K, in La0.67Sr0.33MnO3 (LSMO) nanofibers (NFs) composed of nanoparticles beyond the SPM size (r ≫ r0), resulting in a significant increase of the glass transition temperature. This SGL transition near the TC of bulk LSMO can be explained to be the scenario of locally ordered clusters embedded in a disordered host, in which the assembly of nanoparticles has a magnetic core–shell model driven by surface spin glass. The presence of a surface spin glass of nanoparticles was proved by the Almeida–Thouless line δTf ∝ H2/3, exchange bias, and reduced saturation magnetization of the NF system. Composite dynamics were found – that is, both the SPM and the super-spin-glass (SSG) behavior are found in such an NF system. The bifurcation of the zero-field-cooled (ZFC) and field-cooled (FC) magnetization vs. temperature curves at the ZFC peak, and the flatness of FC magnetization involve SSG, while the frequency-dependent ac susceptibility anomaly follows the Vogel–Fulcher law that implies weak dipole interactions of the SPM model. This finding can help us to find a way to search for high temperature spin glass materials.

Volume

19

Issue

25

First Page

16731

Last Page

16736

DOI

https://doi.org/10.1039/C7CP01276D

ISSN

1463-9076

Comments

ESSN: 1463-9084

Rights

© 2016 Royal Society of Chemistry

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