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Title: Structure and Magnetism of Mn 5Ge 3 Nanoparticles

Abstract

In this work, we investigated the magnetic and structural properties of isolated Mn 5Ge 3 nanoparticles prepared by the cluster-beam deposition technique. Particles with sizes between 7.2 and 12.6 nm were produced by varying the argon pressure and power in the cluster gun. X-ray diffraction (XRD)and selected area diffraction (SAD) measurements show that the nanoparticles crystallize in the hexagonal Mn 5Si 3-type crystal structure, which is also the structure of bulk Mn 5Ge 3. The temperature dependence of the magnetization shows that the as-made particles are ferromagnetic at room temperature and have slightly different Curie temperatures. Hysteresis-loop measurements show that the saturation magnetization of the nanoparticles increases significantly with particle size, varying from 31 kA/m to 172 kA/m when the particle size increases from 7.2 to 12.6 nm. The magnetocrystalline anisotropy constant K at 50 K, determined by fitting the high-field magnetization data to the law of approach to saturation, also increases with particle size, from 0.4 × 10 5 J/m 3 to 2.9 × 10 5 J/m 3 for the respective sizes. This trend is mirrored by the coercivity at 50 K, which increases from 0.04 T to 0.13 T. A possible explanation for the magnetization trend is amore » radial Ge concentration gradient.« less

Authors:
 [1];  [1];  [2];  [2];  [2];  [1]
  1. Univ. of Delaware, Newark, DE (United States). Dept. of Physics and Astronomy
  2. Univ. of Nebraska, Lincoln, NE (United States). Dept. of Physics and Astronomy and Nebraska Center for Materials and Nanoscience
Publication Date:
Research Org.:
Univ. of Nebraska, Lincoln, NE (United States); Univ. of Delaware, Newark, DE (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1511046
Grant/Contract Number:  
FG02-04ER46152; FG02-90ER45413
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nanomaterials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 4; Journal ID: ISSN 2079-4991
Publisher:
MDPI
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; magnetic nanoparticles; cluster deposition; magnetization

Citation Formats

Tosun, Onur, Salehi-Fashami, Mohammed, Balasubramanian, Balamurugan, Skomski, Ralph, Sellmyer, David J., and Hadjipanayis, George. Structure and Magnetism of Mn5Ge3 Nanoparticles. United States: N. p., 2018. Web. doi:10.3390/nano8040241.
Tosun, Onur, Salehi-Fashami, Mohammed, Balasubramanian, Balamurugan, Skomski, Ralph, Sellmyer, David J., & Hadjipanayis, George. Structure and Magnetism of Mn5Ge3 Nanoparticles. United States. doi:10.3390/nano8040241.
Tosun, Onur, Salehi-Fashami, Mohammed, Balasubramanian, Balamurugan, Skomski, Ralph, Sellmyer, David J., and Hadjipanayis, George. Sun . "Structure and Magnetism of Mn5Ge3 Nanoparticles". United States. doi:10.3390/nano8040241. https://www.osti.gov/servlets/purl/1511046.
@article{osti_1511046,
title = {Structure and Magnetism of Mn5Ge3 Nanoparticles},
author = {Tosun, Onur and Salehi-Fashami, Mohammed and Balasubramanian, Balamurugan and Skomski, Ralph and Sellmyer, David J. and Hadjipanayis, George},
abstractNote = {In this work, we investigated the magnetic and structural properties of isolated Mn5Ge3 nanoparticles prepared by the cluster-beam deposition technique. Particles with sizes between 7.2 and 12.6 nm were produced by varying the argon pressure and power in the cluster gun. X-ray diffraction (XRD)and selected area diffraction (SAD) measurements show that the nanoparticles crystallize in the hexagonal Mn5Si3-type crystal structure, which is also the structure of bulk Mn5Ge3. The temperature dependence of the magnetization shows that the as-made particles are ferromagnetic at room temperature and have slightly different Curie temperatures. Hysteresis-loop measurements show that the saturation magnetization of the nanoparticles increases significantly with particle size, varying from 31 kA/m to 172 kA/m when the particle size increases from 7.2 to 12.6 nm. The magnetocrystalline anisotropy constant K at 50 K, determined by fitting the high-field magnetization data to the law of approach to saturation, also increases with particle size, from 0.4 × 105 J/m3 to 2.9 × 105 J/m3 for the respective sizes. This trend is mirrored by the coercivity at 50 K, which increases from 0.04 T to 0.13 T. A possible explanation for the magnetization trend is a radial Ge concentration gradient.},
doi = {10.3390/nano8040241},
journal = {Nanomaterials},
issn = {2079-4991},
number = 4,
volume = 8,
place = {United States},
year = {2018},
month = {4}
}

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