Phonons as a Probe of the Low Temperature Metal Insulator Transition in Na.75Co.95Ni.05O2

Nickel substitution at the cobalt site in NaxCoO2 induces a Metal Insulator Transition (MIT) and the temperature at which this occurs (TMIT) increases with Ni content. Low temperature far infrared measurements on polycrystalline samples of Na0.75CoO2 and Na0.75Co0.95Ni0.05O2 (TMIT = ~ 150K) were car...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2005-10
Main Authors: Premila, M, Bharathi, A, Yasodha, P, N Gayathri Y Hariharan, Sundar, C S
Format: Article
Language:English
Subjects:
Nickel
Sodium
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Nickel substitution at the cobalt site in NaxCoO2 induces a Metal Insulator Transition (MIT) and the temperature at which this occurs (TMIT) increases with Ni content. Low temperature far infrared measurements on polycrystalline samples of Na0.75CoO2 and Na0.75Co0.95Ni0.05O2 (TMIT = ~ 150K) were carried out to look for signatures of this transition. While both the samples show an evident splitting of the high frequency Co-O mode on lowering the temperature, dramatic changes are observed in the low frequency sodium mode in Na0.75Co0.95Ni0.05O2 clearly pointing out to an ordering of the sodium ions in the low temperature insulating state.
ISSN:2331-8422