@article {45978,
	title = {Identification of the Zn substitution sites in La-Zn substituted SrAl12O19 from Al-27 solid-state NMR studies},
	journal = {Journal of the American Ceramic Society},
	volume = {97},
	year = {2014},
	month = {SEP},
	pages = {2990-2995},
	type = {Article},
	abstract = {<p>The La-Zn substituted hexagonal strontium aluminate, Sr1-xLaxAl12-xZnxO19, with the magnetoplumbite structure and having five different coordination environments for Al with different symmetries, is investigated using Al-27 solid-state NMR to get detailed information on the sites of substitution of Zn and the associated changes in the local coordination environments of Al. The objective of the study was to get information on the local structural variations in the isostructural La-Co substituted strontium ferrite, Sr1-xLaxFe12-xCoxO19, showing enhanced magnetic performance on substitution. The NMR studies on the aluminate give direct evidence for the sites of substitution and the changes in the local coordination environments. It is found that Zn is substituted at the 2a and 4f(2) AlO6 octahedral sites. However, an interesting observation from the NMR studies is the stabilization of the Al site occupancy at the penta-coordinated 2b site over the distorted tetrahedral 4eAl site, without any substitution at these sites. Large changes in the quadrupolar coupling constant of the 2a and 4e sites are observed between x=0.2 and 0.3, corresponding to the compositional region showing higher performance in the case of Sr1-xLaxFe12-xCoxO19, indicating the role of distortion of local coordination environments on suitable substitution in controlling the performance parameters.</p>},
	issn = {0002-7820},
	doi = {10.1111/jace.13029},
	author = {Baby, Bindhu and Dey, Krishna K. and Ajithkumar, Thalasseril G. and Joy, Pattayil A.}
}
@article { ISI:000328952500024,
	title = {Investigations into variations in local cationic environment in layered oxide series InGaO3(ZnO)(m) (m=1-4)},
	journal = {Dalton Transactions},
	volume = {43},
	number = {5},
	year = {2014},
	month = {NOV},
	pages = {2120-2126},
	publisher = {ROYAL SOC CHEMISTRY},
	address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND},
	abstract = {<p>Layered oxides of the series InGaO3(ZnO)(m) (m = 1-4) are interesting due to their structural anisotropy. Here, we report a comprehensive study of their structural details, focusing on the local cationic environment in bulk powder samples by MASNMR and EXAFS, which is hitherto not attempted. It is found that the Ga geometry varies gradually from pure pentacoordinated to a mixture of penta and tetracoordinated with increasing amounts of tetracoordination as we move across the series, contrary to previous reports suggesting exclusively trigonal bipyramidal coordination in all the compounds. A similar observation is also made in the case of Zn and structural evolution involving the dissolution of Ga in a ZnO4 tetrahedral network in a sandwich layer can be discerned, as the insulating ZnO layer size increases.</p>},
	issn = {1477-9226},
	doi = {10.1039/c3dt52011k},
	author = {Narendranath, Soumya B. and Yadav, Ashok Kumar and Ajithkumar, Thalasseril G. and Bhattacharyya, Dibyendu and Jha, Shambhu Nath and Dey, Krishna K. and Raja, Thirumalaiswamy and Devi, R. Nandini}
}
