The results of magnetoresistance measurements on a naturally occurring multilayer which is ferromagnetic below 326 K, are reported. The magnitude of magnetoresistance is found to be positive below 70 K gradually increasing to an unusually large value (nearly 100%) at 4.2 K in the presence of a field of 70 kOe as the temperature is lowered, similar to the recent observations by Verbanck, Temst, Mae, Schad, Van Bael, Moshchalkov, and Bruynseraede [Appl. Phys. Lett. 70, 1477 (1997)] in Cr/Ag/Cr trilayers. The positive sign of magnetoresistance for a ferromagnet is unexpected and possible explanations are offered.
REFERENCES
1.
See, for instance,
G.
Binasch
, P.
Grünberg
, F.
Saurenbach
, and W.
Zinn
, Phys. Rev. B
39
, 4828
(1989
);M. N.
Baibich
, J. M.
Broto
, A.
Fert
, F.
Nguyen van Dau
, F.
Petroff
, P.
Eitenne
, G.
Creuzet
, A.
Freiderich
, and J.
Chazelas
, Phys. Rev. Lett.
61
, 2472
(1988
);R.
Schad
, C. D.
Potter
, P.
Belien
, G.
Verbanck
, V. V.
Moschalkov
, and Y.
Bruynseraede
, Appl. Phys. Lett.
64
, 3500
(1994
);see, also,
E.
Fullerton
, Appl. Phys. Lett.
63
, 1699
(1993
), and references therein.2.
R.
Van Helmdt
, J.
Wecker
, B.
Holzapfel
, L.
Schultz
, and K.
Samner
, Phys. Rev. Lett.
71
, 2331
(1993
); see,3.
I.
Das
and E. V.
Sampathkumaran
, J. Magn. Magn. Mater.
137
, L239
(1994
);For our recent report on GdNi, see,
R.
Mallik
, E. V.
Sampathkumaran
, P. L.
Paulose
, and V.
Nagarajan
, Phys. Rev. B
55
, R8650
(1997
).4.
See a review, A. Szytula and J. Leciejewicz, in Handbook on the Physics and Chemistry of Rare Earths, edited by K. A. Gscheneidner and L. Eyring (Elsevier, New York, 1989), Vol. 12, p. 133, and references therein.
5.
E. V.
Sampathkumaran
, P. L.
Paulose
, and R.
Mallik
, Phys. Rev. B
54
, R3710
(1996
);R. B.
van Dover
, E. M.
Gyorgy
, R. J.
Cava
, J. J.
Krajewski
, R. J.
Felder
, and W. F.
Peck
, Phys. Rev. B
47
, 6134
(1993
);J. H. V. J.
Brabers
, K.
Bakker
, H.
Nakone
, F. R.
de Boer
, S. K.
Lenczowski
, and K. H. J.
Buschow
, J. Alloys. Compd.
199
, L1
(1993
);J. S.
Lord
, R. C.
Riedi
, G. J.
Tomka
, Cz.
Kapusta
, and K. H. J.
Buschow
, Phys. Rev. B
53
, 283
(1996
).6.
G.
Verbanck
, K.
Temst
, K.
Mae
, R.
Schad
, M. J.
van Bael
, V. V.
Moshchalkov
, and Y.
Bruynseraede
, Appl. Phys. Lett.
70
, 1477
(1997
).7.
I.
Nowik
, Y.
Levi
, I.
Felner
, and E. R.
Bauminger
, J. Magn. Magn. Mater.
140–144
, 913
(1995
);I.
Nowik
, Y.
Levi
, I.
Felner
, and E. R.
Bauminger
, J. Magn. Magn. Mater.
147
, 373
(1995
).8.
G.
Venturini
, B.
Malaman
, and E.
Ressouche
, J. Alloys Compd.
241
, 135
(1996
);G.
Venturini
, R.
Welter
, E.
Ressouche
, and B.
Malaman
, J. Magn. Magn. Mater.
150
, 197
(1995
).
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