Electrical and magnetic properties of 3d-transition metal vanadates

Palanna, O. G. ; Shashi Mohan, A. L. ; Biswas, A. B. (1977) Electrical and magnetic properties of 3d-transition metal vanadates Proceedings of the Indian Academy of Sciences - Mathematical Sciences, 86 (5). pp. 455-463. ISSN 0253-4142

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Official URL: http://www.ias.ac.in/j_archive/proca/86/5/455-463/...

Related URL: http://dx.doi.org/10.1007/BF03046877


The electrical and magnetic properties of vanadates of the general formula (MO)n .V2O5, where M=Mn, Co, Ni, Cu and Zn, and n=1, 2 and 3, are discussed. Conduction in these materials occurs due to small deviations from the stoichiometric composition in the form of anion-(n-type) or cation-(p-type) vacancies. The mechanism of electrical transport is of a thermally activated hopping of charge carriers on equivalent cation lattice sites. It has been found that the meta vanadates (n=1) are alln-type while the pyro-(n=2) and ortho-(n=3) compounds of Mn, Co and Ni arep-type; but Cu and Zn analogues remainn-type only. The vanadates obey Curie-Weiss law at 80-340 K. The effective magnetic moments for MV2O6 are nearly the same as spin only values for the magnetic M2+ ions, and diminish with increasing MO contents. The predominant exchange interactions are the weak 90°MOM super-exchange and M-O-O-M super-super exchange. The Weiss constant is negative (antiferro-) for all the compounds except Co3V2O8 which has a positive (ferro-) value. Cooperative phenomena, if any, have not been observed in this temperature range.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Stoichiometric Compositions; Charge Carriers; Hopping Conduction; Exchange Interactions
ID Code:81150
Deposited On:04 Feb 2012 07:47
Last Modified:18 May 2016 22:49

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