Stoichiometry determined exchange interactions in amorphous ternary transition metal oxides: Theory and experiment

Journal Article · Mon Jul 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4891474· OSTI ID:22308535

Hu, Shu-jun; Yan, Shi-shen; Zhang, Yun-peng; Zhao, Ming-wen; Kang, Shi-shou; Mei, Liang-mo ^[1]

---

1. School of Physics, National Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100 (China)

Amorphous transition metal oxides exhibit exotic transport and magnetic properties, while the absence of periodic structure has long been a major obstacle for the understanding of their electronic structure and exchange interaction. In this paper, we have formulated a theoretical approach, which combines the melt-quench approach and the spin dynamic Monte-Carlo simulations, and based on it, we explored amorphous Co{sub 0.5}Zn{sub 0.5}O{sub 1−y} ternary transition metal oxides. Our theoretical results reveal that the microstructure, the magnetic properties, and the exchange interactions of Co{sub 0.5}Zn{sub 0.5}O{sub 1−y} are strongly determined by the oxygen stoichiometry. In the oxygen-deficient sample (y > 0), we have observed the long-range ferromagnetic spin ordering which is associated with the non-stoichiometric cobalt-rich region rather than metallic clusters. On the other hand, the microstructure of stoichiometric sample takes the form of continuous random networks, and no long-range ferromagnetism has been observed in it. Magnetization characterization of experimental synthesized Co{sub 0.61}Zn{sub 0.39}O{sub 1−y} films verifies the relation between the spin ordering and the oxygen stoichiometry. Furthermore, the temperature dependence of electrical transport shows a typical feature of semiconductors, in agreement with our theoretical results.

• OSTI ID: 22308535
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 4; 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
AMORPHOUS STATE
COBALT COMPOUNDS
COMPUTERIZED SIMULATION
ELECTRONIC STRUCTURE
EXCHANGE INTERACTIONS
FERROMAGNETISM
FILMS
MAGNETIC PROPERTIES
MAGNETIZATION
MICROSTRUCTURE
MONTE CARLO METHOD
OXIDES
OXYGEN COMPOUNDS
PERIODICITY
SEMICONDUCTOR MATERIALS
SPIN
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS