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Journal article
Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity
Low temperature physics (Woodbury, N.Y.), v 28(7), pp 562-568
Jul 2002
Abstract
We present the results of our extensive Mössbauer effect studies carried out on a wide variety of mixed valence manganites as well as other types of magnetoresistive materials, including pyrochlore
Tl
2
Mn
2
O
7
and the chalcospinels
Fe
0.5
Cu
0.5
Cr
2
S
4
and
FeCr
2
S
4
with absolutely different natures of the magnetism, in a search for similarities linked to their magnetoresistive behavior. The double exchange electron transfer and coupling between the electrons and Jahn–Teller lattice distortions invoked by most theories to explain the colossal magnetoresistivity and associated metal–insulator transition in manganites are not applicable to pyrochlore nor to chalcospinels. Nevertheless, we find intriguing similarities in the anomalous magnetic and dynamic behavior among these widely different systems at, above, and below the Curie temperature
T
C
,
which shed light on the origin of bulk magnetoresistivity in general. All these compounds share the following features. The long-range ferromagnetic order breaks down even below the Curie temperature, with the formation of nano-size spin clusters. Softening of the lattice was observed near
T
C
.
The short-range interactions in these spin clusters survive well above
T
C
.
When an external magnetic field is applied, the spin clusters coalesce to form large clusters, with considerable lowering of the resistivity. There is a strong evidence that the existence of nano-size spin clusters with superparamagnetic-like behavior near
T
C
is a prerequisite for the occurrence of bulk magnetoresistivity.
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Details
- Title
- Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity
- Creators
- V. Chechersky - Department of Chemistry, Drexel University, Philadelphia, Pennsylvania 19104, USAA. Nath - Drexel University
- Publication Details
- Low temperature physics (Woodbury, N.Y.), v 28(7), pp 562-568
- Publisher
- American Institute of Physics (AIP)
- Number of pages
- 7
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]
- Web of Science ID
- WOS:000177042900014
- Scopus ID
- 2-s2.0-0036339498
- Other Identifier
- 991019168433104721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Physics, Applied