MAGNETISM ELECTRON TRANSPORT MAGNETORESISTIVE LANTHANUM CALCIUM MANGANITE

Critical Behavior and Anisotropy in Single Crystal SrRuO 3
T 2 Coefficient (10 -6 /K 2 )
50
40
30
20
10
0
B parameter in fit to M = M 0 (1 - BT 2 )
-10
0 25 50 75 100 125 150
Maximum Temperature of Fitting Range
In fitting to the data on SrRuO 3 single crystal the B parameter (Figure A-9)
is relatively stable and increases as lower temperature fitting ranges (T max ) are
used. The A parameter (Figure A- 8) is not as stable and appears to decrease as
T max is lowered. If this trend were to continue, then the T 3/2 contribution
would be very small at low temperatures. The removal of the AT 3/2 term
further stabilizes the B parameter (Figure A- 10), and makes B more
independent of T max than with AT 3/2 included. Thus, from this analysis of the
magnetization data, there is little evidence for a large AT 3/2 contribution to
the magnetization. This is in contrast with measurements on thin film [186,
187] which show T 3/2 dominating over T 2 .
Θ 2 (K)
240
235
230
233K = √2T
C
expected from
Θ (T = 60K)
2 max
225 simple Stoner Theory
220
Θ = B 2 1/2
215
210
0 1 2 3 4 5 6 7
Internal Field (T)
Figure A- 10. Variation of the T 2 parameter in fitting the
magnetization data of single crystal SrRuO 3 to M = M S (1 - BT 2 )
as the fitting range is increased. The parameter B for this fit is
more stable and constant than that shown in Figure A- 8.
Inset, variation of Θ 2 in a magnetic field.
The two corrections to the spin wave T 3/2 theory mentioned above (finite
magnetic field and higher order T (2n+1)/2 terms) may not adequately explain the
data presented here. The applied magnetic field will suppress spin wave
169