Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Solid State Physics Department
1
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Low Temperature Laboratory
Dr. Raul Rapp
Dr. Miguel Novak
Dr. Artur B. Chaves
Dr. Luis Ghivelder
Dr. J.P.Sinnecker
PhD Students
Undergraduate
Students
Post-Doc
2
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Avaiable Equipments
•
Quantum Design PPMS
– ac/dc H<90 kOe, 1.8 K<T<300K
•
SHE Dilution Refrigerator – mK ac susceptibility, resistivity, specific heat
•
14T Cryogenic Magnet – 1.5K up to 300K – resistivity
– VSM will be implemented with a LakeShore HEAD
•
7T Oxford Magnet – 4.2K up to 300K
•
Oxford He3 refrigerator – 300mK specific heat
•
Home Made low filed Hysteresis and Magnetoimpedance
•
Home Made High f ac susceptibility (4.2K up to 300K)
3
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Facilities
• Sample Preparation:
– Arc furnace
– Standard resistive Furnaces
• Liquid He
–
–
–
Liquefier CTI 1400 de 20 lit/h
He Recovery
He Manyfold with 48 cil
• Comercial LN2
• Small Workshop
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Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Future Equipments
• 6T Cryogenic SQUID
– Ac susceptibility
• 14T VSM
– LAKESHORE Head with Brazilian Vibrating Driver (GLOBALMAG)
• 7T Specific Heat – Magnetocaloric Effect
• PULSE FIELD
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Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Research Lines
Mn12
• Molecular Magnetism
–
–
–
–
Nanoscale Magnetism
Quantum Effects
Low dimensions
Chemistry
• Strong interactions with
Chemistry and Theoretical
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M.Novak, J.P.Sinnecker, R. Rapp, A.Chaves
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Linhas de Pesquisa
• Molecular Magnets
Co(hfac)2(NITPhOMe) chains
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Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Research Lines
20
(a)
CdFe2O4
– Ferrofluids
• Biocompatible
– cancer
• Polimeric Matrix
Hcoolling=0Oe
15
Hac=2Oe
-3
χ' [ emu/Oe x 10 ]
• Nanomagnetic Materials
10
5
0
– ambiental
• UnB, UFG
-3
– CTPETRO
χ'' [ emu/Oe x 10 ]
2.0
(b)
frequency Hz
10
100
1k
10k
1.5
1.0
0.5
0.0
0
50
100
150
200
250
300
Temperature [K]
8
M.Novak, W.C.Nunes, J.P.Sinnecker
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Ferrofluids
-5
-10
5
Log(τ)
6
HDC=200Oe
4
-25
ZFC
FC
(a) high T peak
-2
-4
-6
0.0054
0.0060
-35
0.000 0.001 0.002 0.003 0.004 0.005 0.006
2
-1
1/T [K ]
(a)
1
0
2
Log(τ)
-3
magnetization [x10 emu]
-20
-30
3
1
HDC=50Oe
(b)
0
-15
,
,
-2
-4
(b) low T peak
-6
-8
-10
-12
,
ZFC
-14
,
FC
-16
-18
-20
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
-1
1/T [K ]
0
50
100
150
Temperature [K]
200
250
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Instituto de Física – UFRJ
Departamento de Física dos Sólidos
AC Susceptibility: Vogel-Fulcher
2800
,
,
2600
ZFC
FC
Tp2ln(τ/τ0)
2400
2200
2000
1800
1600
9
10
11
12
13
14
15
16
17
ln(τ/τ0)
10
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
NdFeAl
20
Magnetization [emu/g]
15
1.2
10
5
0
-5
Nd60Fe20Co10Al10
T=300K
-10
ZFC/FC
H=8T
-15
-4
-2
0
NdFeCoAl
2
4
6
8
10
Applied Field [T]
0.8
50
40
0.6
30
0.4
0.2
0
50
100
150
200
Temperature [K]
250
300
Magnetization [emu/g]
Magnetization [emu]
1.0
20
10
0
-10
-20
Nd60Fe20Co10Al10
T=75K
-30
-40
-50
-10
-8
-6
-4
-2
0
2
4
6
8
10
Applied Field [T]
J.P.Sinnecker, M.Novak
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Instituto de Física – UFRJ
Departamento de Física dos Sólidos
Co10Co90
0.6
• CoCu
Magnetization [emu]
0.5
as cast
o
annealed (600 C)
0.4
0.3
0.2
0.1
0
50
100
150
200
250
300
350
Temperature [K]
0.012
Co10Cu90
Magnetization [emu]
0.010
Co3Cu97
0.008
0.006
0.004
0.002
0
50
100
150
200
Temperature [K]
M.Novak, W.C.Nunes, J.P.Sinnecker
250
300
350
12
Instituto de Física – UFRJ
Departamento de Física dos Sólidos
THE END
END