Summary
1
www.postersession.com We report results of transport property of mechanically exfoliated single-crystal Chromium-Doped Bismuth Antimony Telluride nano films . It is found that the ferromagnetism depend on density of carriers which is different from the results of ultrathin films grown by molecular beam epitaxy .In addition we investigate the complex dependence of resistance on temperature, magnetic field to interpret the relation between carrier-mediated interactions and carriers' localization. Summary Transport Property of Chromium-Doped Bismuth Antimony Telluride Nanofilms Qingyan Fan, Bin Li, ， Zhenghua An, Shan Qiao Institute of Advanced Materials and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, PR China References [1] Ohno, Making Nonmagnetic Semiconductors Ferromagnetic, science.281.5379.951 [2] TomaszDietl, Interplay between carrier localization and magnetism in diluted magnetic and ferromagnetic, J. Phys. Soc. Jpn. 77 (2008). [3] Liu, Minhao el, Crossover between Weak Antilocalization and Weak Localization in a Magnetically Doped Topological Insulator. Phys.Rev.Lett.108.036805 We report results of transport property of mechanically exfoliated single-crystal Chromium-Doped Bismuth Antimony Telluride nano films .The ferromagnetic state was confirmed by the presence of the anomalous Hall effect. The Curie temperature is proportional to the density of holes which might suggest that the RKKY interaction is at play in the bulk state of the sample . The resistance maximum and the associated negative magnetoresistance near the Curie temperature may be related to disorder-modified carrier- carrier interactions. These interactions account also for the low-temperature increase of resistance. Abstract Electrical and Magnetic Properties (a) SEM image of nanoplates on a 300nm SiO2 substrate. (b) The thicknesses of a plate in nanometer ,measured by Dektak 150. Sample Preparation (a) Temperature dependent longitudinal resistance Rxx of the films Cr 0.2 Sb 1.44 Bi 0.36 Te 3 . (b) Magnetic field dependent Hall resistance Rxy of the films at different temperatures. (c) Magnetoresistance of the films as a perpendicular magnetic field is applied above the Curie temperature (TC) . (d) Raw data of magnetoresistance of the films as a perpendicular magnetic field is applied below the Curie temperature (TC) . Results Localization Property and Ferromagnetism 0.00 0.18 0.36 0.54 4 8 12 16 20 Tm /K T c/K T/K B icon te nt(x) (a) Magnetic and electric properties of Cr-doped Sb 1.8 Bi 0 Te 3 films . (b) Magnetic field dependent Hall resistance Ryx of the Cr 0.2 Sb 1.8 Bi 0 Te 3 films at different temperatures. Temperature dependent longitudinal resistance Rxx of the films Anomalous Hall effect of the Cr0.2Sb(1.8-X)BixTe3 film at T=2K. Dependence of (a) carrier density and (b) Curie temperature (TC) on Bi content (x). Error bars represent temperature spacing in RAH-T measurements. Dependence of Curie temperature (red) and Tm (blue) on Bi content (x). Error bars represent temperature spacing in RAH-T and Rxx-T measurements. 10 20 30 40 3.2 3.3 3.4 C r0.2S b 1.44B i0.36T e3 R xx/ T/K T m -40000 -20000 0 20000 40000 2.9 3.0 3.1 3.2 3.3 C r0.2S b 1.44B i0.36T e3 2K 5K 7K 10K 12K R xx/ B /oe -40000 -20000 0 20000 40000 -0.08 -0.06 -0.04 -0.02 0.00 C r0.2S b 1.44B i0.36T e3 12K 15K 17K 19K 25K 30K 60K R xx(B) B /oe -1000 -500 0 500 1000 -0.2 0.0 0.2 C r0.2S b 1.44B i0.36T e3 2K 7K 10K 12K 13K R xy/ B /oe (d) (b) (a) (c) 0.00 0.18 0.36 0.54 1.00E+025 2.00E+025 3.00E+025 C r0.2S b (1.8-X )B ixT e3 n ( m -3 ) B ico n te n t(x) (a) 0.00 0.18 0.36 0.54 4 8 12 16 20 C r0.2S b (1.8-X )B ixT e3 T c/K B ico n te n t(x) (b) (a) -1000 -500 0 500 1000 -0.4 -0.2 0.0 0.2 C r0.2S b 1.8B i0T e3 2K 5K 10K 16K 17K 18K 19K R xy/ B /oe (a) 0 25 50 75 100 3 .0 3 .5 4 .0 4 .5 C r0.2S b 1.8B i0T e3 R xx/ T /K (b) (b) 100 120 140 160 180 200 0 20 40 60 80 d/nm x/u m Curie temperature and Carrier Concentration
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Transport Property of Chromium-Doped Bismuth Antimony Telluride Nanofilms Qingyan Fan, Bin Li, ， Zhenghua An, Shan Qiao Institute of Advanced Materials and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, PR China. Localization Property and Ferromagnetism. - PowerPoint PPT Presentation
Transcript of Summary
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www.postersession.com
We report results of transport property of mechanically exfoliated single-crystal
Chromium-Doped Bismuth Antimony Telluride nano films . It is found that the
ferromagnetism depend on density of carriers which is different from the results of
ultrathin films grown by molecular beam epitaxy .In addition we investigate the
complex dependence of resistance on temperature, magnetic field to interpret the
relation between carrier-mediated interactions and carriers' localization.
Summary
Transport Property of Chromium-Doped
Bismuth Antimony Telluride Nanofilms
Qingyan Fan, Bin Li, ， Zhenghua An, Shan QiaoInstitute of Advanced Materials and State Key Laboratory of Surface Physics, Fudan University,
Shanghai 200433, PR China
References[1] Ohno, Making Nonmagnetic Semiconductors Ferromagnetic,
science.281.5379.951
[2] TomaszDietl, Interplay between carrier localization and magnetism in
diluted magnetic and ferromagnetic, J. Phys. Soc. Jpn. 77 (2008). [3] Liu, Minhao el, Crossover between Weak Antilocalization and Weak
Localization in a Magnetically Doped Topological Insulator. Phys.Rev.Lett.108.036805
We report results of transport property of mechanically exfoliated single-crystal
Chromium-Doped Bismuth Antimony Telluride nano films .The ferromagnetic state
was confirmed by the presence of the anomalous Hall effect. The Curie temperature
is proportional to the density of holes which might suggest that the RKKY interaction
is at play in the bulk state of the sample . The resistance maximum and the
associated negative magnetoresistance near the Curie temperature may be related
to disorder-modified carrier-carrier interactions. These interactions account also for
the low-temperature increase of resistance.
Abstract
Electrical and Magnetic Properties
(a) SEM image of nanoplates on a 300nm SiO2 substrate. (b) The thicknesses
of a plate in nanometer ,measured by Dektak 150.
Sample Preparation
(a) Temperature dependent longitudinal resistance Rxx of the films Cr0.2Sb1.44Bi0.36Te3 . (b) Magnetic field dependent Hall resistance Rxy of the films at different temperatures. (c) Magnetoresistance of the films as a perpendicular magnetic field is applied above the Curie temperature (TC) . (d) Raw data of magnetoresistance of the films as a perpendicular magnetic field is applied below the Curie temperature (TC) .
Results
Localization Property and Ferromagnetism
0.00 0.18 0.36 0.544
8
12
16
20
Tm/K Tc/K
T/K
Bi content(x)(a) Magnetic and electric properties of Cr-doped Sb1.8Bi0Te3 films . (b) Magnetic
field dependent Hall resistance Ryx of the Cr0.2Sb1.8Bi0Te3 films at different
temperatures. Temperature dependent longitudinal resistance Rxx of the films
Anomalous Hall effect of the Cr0.2Sb(1.8-X)BixTe3 film at T=2K. Dependence of
(a) carrier density and (b) Curie temperature (TC) on Bi content (x). Error bars
represent temperature spacing in RAH-T measurements.
Dependence of Curie temperature (red) and Tm (blue) on Bi content (x). Error bars represent temperature spacing in RAH-T and Rxx-T measurements.
10 20 30 40
3.2
3.3
3.4
Cr0.2Sb1.44Bi0.36Te3
Rxx
/T/K
Tm
-40000 -20000 0 20000 40000
2.9
3.0
3.1
3.2
3.3
Cr0.2Sb1.44Bi0.36Te3
2K 5K 7K 10K 12K
Rxx/
B/oe-40000 -20000 0 20000 40000
-0.08
-0.06
-0.04
-0.02
0.00
Cr0.2Sb1.44Bi0.36Te3
12K 15K 17K 19K 25K 30K 60K
Rxx
(B)
B/oe
-1000 -500 0 500 1000
-0.2
0.0
0.2
Cr0.2Sb1.44Bi0.36Te3 2K 7K 10K 12K 13K
Rxy/
B/oe
(d)
(b)(a)
(c)
0.00 0.18 0.36 0.54
1.00E+025
2.00E+025
3.00E+025
Cr0.2Sb(1.8-X)BixTe3
n(m
-3)
Bi content(x)
(a)
0.00 0.18 0.36 0.544
8
12
16
20
Cr0.2Sb(1.8-X)BixTe3
Tc/
K
Bi content(x)
(b)
(a)
-1000 -500 0 500 1000-0.4
-0.2
0.0
0.2
Cr0.2Sb1.8Bi0Te3 2K 5K 10K 16K 17K 18K 19K
Rxy
/
B/oe
(a)
0 25 50 75 100
3.0
3.5
4.0
4.5Cr0.2Sb1.8Bi0Te3
Rxx
/
T/K
(b)
(b)
100 120 140 160 180 200
0
20
40
60
80
d/n
m
x/um
Curie temperature and Carrier Concentration
