Investigation of cation distribution, electrical, magnetic properties and their correlation in Mn{sub 2-x}Co{sub 2x}Ni{sub 1-x}O{sub 4} films

Journal Article · Fri Mar 21 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4868683· OSTI ID:22271197

Wu, Jing; Huang, Zhiming; Zhou, Wei; Ouyang, Cheng; Gao, Yanqing ^[1]; Hou, Yun; Chu, Junhao ^[1]; Chen, Ren ^[2]

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1. National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083 (China)
2. No.3 Department, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083 (China)

X-ray photoelectron spectroscopy was performed on Mn{sub 2-x}Co{sub 2x}Ni{sub 1-x}O{sub 4} (x = 0.2, 0.4, 0.5, 0.6, and 0.8) series spinel films to determine their cation distributions. The results show that both Ni and Co ions exhibit bivalence, while Mn ions exhibit coexisting multivalence. The hopping frequency ν{sub 0} of each sample was obtained by combining cation distribution results and electrical measurement data. Analysis of the divergence at Neel temperature between field cooling and zero-field cooling magnetization curves revealed that the ferromagnetic coupling between octahedral site ions first leads to spontaneous magnetization at T{sub C}, after which a second spontaneous magnetization arises from the antiferromagnetic couple between tetrahedral and octahedral sites at a lower temperature T{sub N}. The correlation between hopping conductivity and magnetic transition temperature is discussed. We propose that the strength of the ferromagnetic couple between octahedral sites is subject to the product term of Nc(1 − c)ν{sub 0}, which determines the ferromagnetic transition temperature (T{sub C}) of the system. Our results provide an avenue to understand the origin of magnetic interaction in small-polaron hopping semiconductors.

• OSTI ID: 22271197
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
CATIONS
COBALT COMPOUNDS
COBALT IONS
CONCENTRATION RATIO
CORRELATIONS
FERROMAGNETISM
FILMS
MAGNETIC PROPERTIES
MAGNETIZATION
MANGANESE COMPOUNDS
MANGANESE IONS
NEEL TEMPERATURE
NICKELATES
SEMICONDUCTOR MATERIALS
X-RAY PHOTOELECTRON SPECTROSCOPY