We report measurements of 1/f electrical noise in two hole doped manganite perovskite oxides, La0.67Ca0.33MnO3 and Pr0.67Sr0.33MnO3, which exhibit colossal magnetoresistance. The noise magnitude represented by the Hooge parameter is nearly 8 orders of magnitude larger than that observed in ordinary metals (and semiconductors) and nearly 5–6 orders of magnitude larger than that observed in epitaxial films of the perovskite oxide YBa2Cu3O7 in the normal state. The normalized noise spectral density increases with decreasing temperature below the resistivity peak, suggestive of the presence of additional low energy noise processes in the ferromagnetic metallic state.
REFERENCES
1.
2.
R.
Von Helmlot
,J.
Weckerg
,B.
Holzapfel
,L.
Schultz
, andK.
Samwer
, Phys. Rev. Lett.
71
, 2331
(1993
). 3.
S.
Jin
,T. H.
Tiefel
,M.
McCormack
,R. A.
Fastnacht
,R.
Ramesh
, andL. H.
Chen
, Science
264
, 413
(1994
). 4.
G. C.
Xiong
,Q.
Li
,H. L.
Ju
,S. N.
Mao
,L.
Senapati
,X. X.
Xi
,R. L.
Greene
, andT.
Venkatesan
, Appl. Phys. Lett.
66
, 1427
(1995
). 5.
R.
Mahendiran
, R.
Mahesh
, N.
Rangavittal
, S. K.
Tiwary
, A. K.
Raychaudhuri
, T. V.
Ramakrishnan
, and C. N. R.
Rao
, Phys. Rev. B
53
, 3348
(1996
). 6.
M.
Rajeswari
, C. H.
Chen
, A.
Goyal
, C.
Kwon
, M. C.
Robson
, R.
Ramesh
, T.
Venkatesan
, and S.
Lakeou
, Appl. Phys. Lett.
68
, 3555
(1996
).7.
8.
9.
M. Rajeswari, S. Lakeou, E. A. Wood, D. D. Choughule, and T. Venkatesan, J. Superconductivity (to be published).
10.
11.
H. T.
Hardner
,S. S. P.
Parkin
,M. B.
Weissman
,M. B.
Salamon
, andE.
Kita
, J. Appl. Phys.
75
, 6533
(1994
).12.
H. L.
Ju
,J.
Gopalakrishnan
,J. L.
Peng
,Q.
Li
,G. C.
Xiong
,T.
Venkatesan
, andR. L.
Greene
, Phys. Rev. B
51
, 6143
(1995
).
This content is only available via PDF.
© 1996 American Institute of Physics.
1996
American Institute of Physics
You do not currently have access to this content.