Marko Jerčinović1,
Tihomir Car1,
Nikola Radić1
Jovica Ivkov2
1Ruđer
Bošković Institute,
Bijenička cesta 54, 10000
Zagreb, Croatia
2Institute for Physics, Bijenička
cesta 46, 10000 Zagreb, Croatia
Introduction & motivation
 Amorphous alloys of early transition – late transition (TE-TL)
metals are interesting because of their good mechanical and
corosion properties
 Al-TE alloys are
amorphous in a wide range
of compositions
 For the application of
these alloys at elevated
temperatures it is
important to investigate
their thermal stability by
study of relaxation and
crystallization kinetics
Sample preparation
 Kurt J. Lesker CMS-18 Magnetron Sputtering System
 Preparation conditions:
 Residual pressure: 2.6 x 10-6 Pa
 Working gas (Ar) Pressure: 0.66 Pa
 Temperature: ~ 293 K
 Substrate: alumina ceramics
4 magnetrons
shutters
magnetron
Electrical measurements
 The isochronal resistivity measurements were performed by
the four-probe method and by standard ac technique with the
computer controlled data acquisition.
 The samples were radiatively heated in a vacuum chamber at a
pressure of about 10-3 Pa.
 The exact thickness of the films investigated is of no
importance, since all the results obtained were normalized to
the electrical resistance at the room temperature.
 Assuming the linear dependence of resistivity with
temperature (R/RRT ~ α·ΔT) in the observed temperature
interval (RT – 400°C), the relaxation effects were extracted
from the R(T) dependence.
Relative resistivity vs. temperature
(w/o linear dependence)
Al-Mo alloy – different compositions
0.10
R/RRT-(1+*(T-TRT))
Al80Mo20
Al75Mo25
0.05
Al70Mo30
0.00
-0.05
-0.10
0
100
200
300
T (OC)
400
500
Relative resistivity vs. temperature
(w/o linear dependence)
Al-TE alloy – different TE metal
0.2
R/RRT-(1+*(T-TRT))
Al75Mo25
Al75Ta25
0.1
Al75W25
0.0
-0.1
0
100
200
300
T (°C)
400
500
Fitting function
a, b, c – parameters
Bloch-Grüneisen
formula [1]
n=2
TS – temperature shift
qD – Debye temperature
Law of modified addition [2]:
r – density
[1] D. Cvijović, Theoretical and Mathematical Physics 166(1), 37–42 (2011)
[2] S. Stoimenov et al, Journal of Materials Science: Materials in Electronics 14, 777–778 (2003)
Fitted curves
Al-Mo alloy – different compositions
R/RRT-(1+*(T-TRT))
Al80Mo20
Al75Mo25
Al70Mo30
(T-Ts) / qD
Fitted curves
R/RRT-(1+*(T-TRT))
Al-TE alloy – different TE metal
Al75W25
Al75Ta25
Al75Mo25
(T-Ts) / qD
Fitted parameters
alloy
θD (K)
Ts (K)
a
b
c
Al80Mo20
439.0
400
0.661
-0.461
-0.0252
Al75Mo25
437.5
384
1.000
-0.781
-0.0473
Al70Mo30
436.1
396
0.724
-0.658
-0.0459
Al75W25
419.3
340
0.351
-0.086
-5·10-4
Al75Ta25
340.5
340
0.127
-0.036
-8·10-4
Conclusion
 Assuming linear temperature dependence of resistivity, relaxation
effects were extracted and fitted to a modified Bloch-Grüneisen
formula
 The fit is reasonably good in
the measured temperature
range (RT – 400°C), for
various compositions and
alloying TE metals
 It remains to find out the
physical meaning of the
fitted parameters and to
extend the research to other
amorphous alloys of various
compositions
~ x5
~ x3
~ x2
~x