Transition temperature of wurtzite CoO nanocrystals as revealed in comprehensive magnetic characterization

Xuemin He; Wei Zhong; Shiming Yan; Chao Liu; Huigang Shi; Chak Tong Au; Youwei Du

doi:10.1021/jp501313r

Transition temperature of wurtzite CoO nanocrystals as revealed in comprehensive magnetic characterization

Xuemin He, Wei Zhong^*, Shiming Yan, Chao Liu, Huigang Shi, Chak Tong Au, Youwei Du

^*Corresponding author for this work

Department of Chemistry

Research output: Contribution to journal › Journal article › peer-review

18 Citations (Scopus)

Abstract

We conducted magnetic study over wurtzite CoO nanocrystals (about 45 nm in size). The blocking temperature T_B and Néel temperature T_N were confirmed by comprehensive magnetic characterization. Below T_B of ∼7 K the nanocrystals exhibit coercivity of 400 Oe and exchange bias of 206 Oe ascribable to composition influences of uncompensated surface spins as well as to antiferromagnetic volume phase. The uncompensated magnetic sublattice and the spatial distribution of the anisotropy axis relative to the magnetic field are proposed to be responsible for the distinct electron spin resonance (ESR) line shape. Based on the temperature dependence of ESR intensity, the accurate T_N is found to be 245 K. It is observed that there is anomalous change in resonance field and line width around T_N.

Original language	English
Pages (from-to)	13898-13903
Number of pages	6
Journal	Journal of Physical Chemistry C
Volume	118
Issue number	25
DOIs	https://doi.org/10.1021/jp501313r
Publication status	Published - 26 Jun 2014

Scopus Subject Areas

Electronic, Optical and Magnetic Materials
General Energy
Physical and Theoretical Chemistry
Surfaces, Coatings and Films

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@article{a6f82edd64264b84b5b5b00aa9ea6ba6,

title = "Transition temperature of wurtzite CoO nanocrystals as revealed in comprehensive magnetic characterization",

abstract = "We conducted magnetic study over wurtzite CoO nanocrystals (about 45 nm in size). The blocking temperature TB and N{\'e}el temperature TN were confirmed by comprehensive magnetic characterization. Below TB of ∼7 K the nanocrystals exhibit coercivity of 400 Oe and exchange bias of 206 Oe ascribable to composition influences of uncompensated surface spins as well as to antiferromagnetic volume phase. The uncompensated magnetic sublattice and the spatial distribution of the anisotropy axis relative to the magnetic field are proposed to be responsible for the distinct electron spin resonance (ESR) line shape. Based on the temperature dependence of ESR intensity, the accurate TN is found to be 245 K. It is observed that there is anomalous change in resonance field and line width around TN.",

author = "Xuemin He and Wei Zhong and Shiming Yan and Chao Liu and Huigang Shi and Au, {Chak Tong} and Youwei Du",

note = "The authors are grateful to the National Natural Science Foundation (Grants 50801033 and 11174132); the National Key Project for Basic Research (Grants 2011CB922102 and 2012CB932304); the Innovation Program for Doctoral Research of Jiangsu Province (Grant CXZZ13_0035); and PAPD, the People{\textquoteright}s Republic of China, for financial support. ",

year = "2014",

month = jun,

day = "26",

doi = "10.1021/jp501313r",

language = "English",

volume = "118",

pages = "13898--13903",

journal = "Journal of Physical Chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

number = "25",

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TY - JOUR

T1 - Transition temperature of wurtzite CoO nanocrystals as revealed in comprehensive magnetic characterization

AU - He, Xuemin

AU - Zhong, Wei

AU - Yan, Shiming

AU - Liu, Chao

AU - Shi, Huigang

AU - Au, Chak Tong

AU - Du, Youwei

N1 - The authors are grateful to the National Natural Science Foundation (Grants 50801033 and 11174132); the National Key Project for Basic Research (Grants 2011CB922102 and 2012CB932304); the Innovation Program for Doctoral Research of Jiangsu Province (Grant CXZZ13_0035); and PAPD, the People’s Republic of China, for financial support.

PY - 2014/6/26

Y1 - 2014/6/26

N2 - We conducted magnetic study over wurtzite CoO nanocrystals (about 45 nm in size). The blocking temperature TB and Néel temperature TN were confirmed by comprehensive magnetic characterization. Below TB of ∼7 K the nanocrystals exhibit coercivity of 400 Oe and exchange bias of 206 Oe ascribable to composition influences of uncompensated surface spins as well as to antiferromagnetic volume phase. The uncompensated magnetic sublattice and the spatial distribution of the anisotropy axis relative to the magnetic field are proposed to be responsible for the distinct electron spin resonance (ESR) line shape. Based on the temperature dependence of ESR intensity, the accurate TN is found to be 245 K. It is observed that there is anomalous change in resonance field and line width around TN.

AB - We conducted magnetic study over wurtzite CoO nanocrystals (about 45 nm in size). The blocking temperature TB and Néel temperature TN were confirmed by comprehensive magnetic characterization. Below TB of ∼7 K the nanocrystals exhibit coercivity of 400 Oe and exchange bias of 206 Oe ascribable to composition influences of uncompensated surface spins as well as to antiferromagnetic volume phase. The uncompensated magnetic sublattice and the spatial distribution of the anisotropy axis relative to the magnetic field are proposed to be responsible for the distinct electron spin resonance (ESR) line shape. Based on the temperature dependence of ESR intensity, the accurate TN is found to be 245 K. It is observed that there is anomalous change in resonance field and line width around TN.

UR - http://www.scopus.com/inward/record.url?scp=84920641783&partnerID=8YFLogxK

U2 - 10.1021/jp501313r

DO - 10.1021/jp501313r

M3 - Journal article

AN - SCOPUS:84920641783

SN - 1932-7447

VL - 118

SP - 13898

EP - 13903

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 25

ER -

Transition temperature of wurtzite CoO nanocrystals as revealed in comprehensive magnetic characterization

Abstract

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