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Electrical resistivity of metastable Ag-Ni alloys
Solid State Communications,
Vol. 13, pp. 1409—1411, 1973.
Pergamon Press.
Printed in Great Britain
ELECTRICAL RESISTIVITY OF METASTABLE Ag—Ni ALLOYS ER. Tyler, J.R. Clinton and H.L. Luo Department of Applied Physics and Information Science,University of California, San Diego, La Jolla, California 92037, U.S.A. (Received 13 July 1973 by!!. Suhi)
We have successfully prepared solid solution metal films of Ag—Ni with Ni content to 23.4 at.%. Four-probe resistivity measurements were conducted between 2.5 and 300°Kand while no anomalies of the magnetic typewere observed, the temperature dependence of the resistivity indicates significant deviations from Matthiessen’s rule.
Ag AND Ni are known to be immiscible, even in the liquid state. The solid solubiity of Ni in Ag is only 0.012 wt.% at 400°C.’We have prepared solid-solution films of Ag—Ni with the technique of sputtering. These metastable samples are kept at room temperature or below to arrest segregation. This investigation has two purposes: (1) to explore the possibility of miscibility in an intrinsically immiscible system and (ii) to compare the electronic properties of Ag—Ni with the well-studied Cu—Ni system, particularly in regard to the reported anomalies in the electrical resistivity.24 The films were sputtered onto sapphire substrates in an argon atmosphere and ranged in thickness from I to 5 ,.im Film composition was determined by electron microprobe analysis. Substrate temperature during sputtering was found to be a critically important parameter in achieving metastable miscibility, and was held at one of two different ranges throughout each experIment 45—50°C(cooled table) or 200— 250°C(wami table).
structure of Ag and Ni was detected. Magnetization measurements were, however, very sensitive in detecting segregation effect and indicated that: 1. All Ag—Ni samples prepared on the warm substrates were ferromagnetic at room temperature. 2. Samples prepared on cooled substrates with Ni content greater than 25 at.% were also ferromagnetic at room temperature. 3. Samples prepared on cooled substrates with Ni content less than 25 at.% showed no magnetic effects down to 4.2°K.Comparison of the sensitivity of the magnetization apparatus with the bulk moment of Ni leads to the conclusion that less than 0.4% of the Ni in each sample could possess its normal moment. We therefore, conclude that these samples represent well-mixed Ag—Ni solid solutions A few of the non-magnetic samples were photoetched to a Four-probe geometry for resistivity measurements between 23 and 300°K.These results are shown in Fig. I. Each sample shows a normal linear increase in resistivity at higher temperatures, with no evident contribution from magnetic scattering.5 This supports the hypothesis that the Ni is well mixed in the Ag.
X-ray and magnetization measurements were conducted on each sample to determine if a solid solution had been achieved. Small grain size (estimated to be 50— 100A) limited the usefulness of the X-ray measurements, but for specimens with higher Ni content (>25 at.% Ni), both Ag and Ni were positively idenifled. Also, no phase other than the f.c.c.
There is, however, a marked increase in slope with increasing Ni content..A similar breakdown of Matthiessen’s rule of approximately the same 1409
1410
ELECTRICAL RESISTIVITY OF METASTABLE Ag—Ni ALLOYS
Vol. 13. No. 9
53.4.’
55.0
15.5.’ tNS
540 15.0
-.
15.. ~,NI •
13.0
U U U
11.0 1.0
IJ.n.-~ 5.0
---
o
-
So TSMPSRATURS iso ~øo (~K)
FIG. 1. Resistivity of sputtered Ag—Ni films. magnitude has been reported in Ni—Cu6 in disagreement with other work7’8 which showed no significant change in slope for Ni content to 30 at.%. It is not possible to state whether this increase in slope is due to a change in electronic structure which effects the
effective number of current carrying electrons or is due to a change in the scattering processes. The increase in residual resistivity with increasing Ni content is consistent within experimental error with previous measurements on Ni—Cu6’79 in this concentration range.
REFERENCES I. 2.
TANAMANNG.and OELSEN W.,Z. Anorg. Chem. 186, 264 (1930). 1-IOUGHTON R.W., SARACHIK M.P. and KOUVEL J.S.,Phvs. Rev. Len. 25,238 (1970).
Vol. 13, No. 9
ELECTRICAL RESISTIVITY OF METASTABLE Ag-Ni ALLOYS
141 I
3.
SKOSKIEWICZ T. and BARONOWSKI B., Solid State Commun. 7,647 (1969).
4.
CRANGLE J. and BUTCHER P.J.L.,pygVs. Lett. A32,80 (1970).
5.
This is consistent with Ni-Cu where resistivity anomalies begin at about 30 at.% Ni.
6.
SCHROEDERPA., WOLF R. and WOOLAM J.A.,Phys. Rev. 138, A105 (1965).
7.
SVENSSON B., Ann. F&s. 25 (5), 236 (1936).
8.
FEDEROV G.V. and RYABININA NM., Fir. metal. metallowed 29,82 (1970).
9.
LEGVOLD S., PETERSON D.T., BURGART P., HOFER R.J. and VYROSTEK T.A., &II. Am. f%ys. Sot. 18,443 (1973).
Wir haben duMe Schichten aus Ag-Ni-metali hergestellt mit bis zu 23,4% Ni in fester Losung. Die Vierpol-Leitfahigkeit wurde als Funktion der Temperatur zwischen 2,5’ und 300°K gemessen ohne magnetische Anomalien zu finder. Aber die Temperaturabhiingigkeit der Leitfahigkeit weicht wesentlich von der Matthiessen-Regel ab.
Vol. 13, pp. 1409—1411, 1973.
Pergamon Press.
Printed in Great Britain
ELECTRICAL RESISTIVITY OF METASTABLE Ag—Ni ALLOYS ER. Tyler, J.R. Clinton and H.L. Luo Department of Applied Physics and Information Science,University of California, San Diego, La Jolla, California 92037, U.S.A. (Received 13 July 1973 by!!. Suhi)
We have successfully prepared solid solution metal films of Ag—Ni with Ni content to 23.4 at.%. Four-probe resistivity measurements were conducted between 2.5 and 300°Kand while no anomalies of the magnetic typewere observed, the temperature dependence of the resistivity indicates significant deviations from Matthiessen’s rule.
Ag AND Ni are known to be immiscible, even in the liquid state. The solid solubiity of Ni in Ag is only 0.012 wt.% at 400°C.’We have prepared solid-solution films of Ag—Ni with the technique of sputtering. These metastable samples are kept at room temperature or below to arrest segregation. This investigation has two purposes: (1) to explore the possibility of miscibility in an intrinsically immiscible system and (ii) to compare the electronic properties of Ag—Ni with the well-studied Cu—Ni system, particularly in regard to the reported anomalies in the electrical resistivity.24 The films were sputtered onto sapphire substrates in an argon atmosphere and ranged in thickness from I to 5 ,.im Film composition was determined by electron microprobe analysis. Substrate temperature during sputtering was found to be a critically important parameter in achieving metastable miscibility, and was held at one of two different ranges throughout each experIment 45—50°C(cooled table) or 200— 250°C(wami table).
structure of Ag and Ni was detected. Magnetization measurements were, however, very sensitive in detecting segregation effect and indicated that: 1. All Ag—Ni samples prepared on the warm substrates were ferromagnetic at room temperature. 2. Samples prepared on cooled substrates with Ni content greater than 25 at.% were also ferromagnetic at room temperature. 3. Samples prepared on cooled substrates with Ni content less than 25 at.% showed no magnetic effects down to 4.2°K.Comparison of the sensitivity of the magnetization apparatus with the bulk moment of Ni leads to the conclusion that less than 0.4% of the Ni in each sample could possess its normal moment. We therefore, conclude that these samples represent well-mixed Ag—Ni solid solutions A few of the non-magnetic samples were photoetched to a Four-probe geometry for resistivity measurements between 23 and 300°K.These results are shown in Fig. I. Each sample shows a normal linear increase in resistivity at higher temperatures, with no evident contribution from magnetic scattering.5 This supports the hypothesis that the Ni is well mixed in the Ag.
X-ray and magnetization measurements were conducted on each sample to determine if a solid solution had been achieved. Small grain size (estimated to be 50— 100A) limited the usefulness of the X-ray measurements, but for specimens with higher Ni content (>25 at.% Ni), both Ag and Ni were positively idenifled. Also, no phase other than the f.c.c.
There is, however, a marked increase in slope with increasing Ni content..A similar breakdown of Matthiessen’s rule of approximately the same 1409
1410
ELECTRICAL RESISTIVITY OF METASTABLE Ag—Ni ALLOYS
Vol. 13. No. 9
53.4.’
55.0
15.5.’ tNS
540 15.0
-.
15.. ~,NI •
13.0
U U U
11.0 1.0
IJ.n.-~ 5.0
---
o
-
So TSMPSRATURS iso ~øo (~K)
FIG. 1. Resistivity of sputtered Ag—Ni films. magnitude has been reported in Ni—Cu6 in disagreement with other work7’8 which showed no significant change in slope for Ni content to 30 at.%. It is not possible to state whether this increase in slope is due to a change in electronic structure which effects the
effective number of current carrying electrons or is due to a change in the scattering processes. The increase in residual resistivity with increasing Ni content is consistent within experimental error with previous measurements on Ni—Cu6’79 in this concentration range.
REFERENCES I. 2.
TANAMANNG.and OELSEN W.,Z. Anorg. Chem. 186, 264 (1930). 1-IOUGHTON R.W., SARACHIK M.P. and KOUVEL J.S.,Phvs. Rev. Len. 25,238 (1970).
Vol. 13, No. 9
ELECTRICAL RESISTIVITY OF METASTABLE Ag-Ni ALLOYS
141 I
3.
SKOSKIEWICZ T. and BARONOWSKI B., Solid State Commun. 7,647 (1969).
4.
CRANGLE J. and BUTCHER P.J.L.,pygVs. Lett. A32,80 (1970).
5.
This is consistent with Ni-Cu where resistivity anomalies begin at about 30 at.% Ni.
6.
SCHROEDERPA., WOLF R. and WOOLAM J.A.,Phys. Rev. 138, A105 (1965).
7.
SVENSSON B., Ann. F&s. 25 (5), 236 (1936).
8.
FEDEROV G.V. and RYABININA NM., Fir. metal. metallowed 29,82 (1970).
9.
LEGVOLD S., PETERSON D.T., BURGART P., HOFER R.J. and VYROSTEK T.A., &II. Am. f%ys. Sot. 18,443 (1973).
Wir haben duMe Schichten aus Ag-Ni-metali hergestellt mit bis zu 23,4% Ni in fester Losung. Die Vierpol-Leitfahigkeit wurde als Funktion der Temperatur zwischen 2,5’ und 300°K gemessen ohne magnetische Anomalien zu finder. Aber die Temperaturabhiingigkeit der Leitfahigkeit weicht wesentlich von der Matthiessen-Regel ab.