Supported by the National Science Foundation DMR-1202033 (MWM), DMR-1405439 (DRT), DMR-1157490 (NHMFL), and the UF Center for Tomorrow’s Materials (Today!) Mark W. Meisel and Group Members (past and present) Department of Physics and NHMFL, University of Florida Long-standing collaboration with Daniel R. Talham and his Group Department of Chemistry, University of Florida “Molecular Magnetism”: What is it? What it is NOT! or “What I wish I knew when I was in your seat….” Start with a Definition: (but avoid blathering….. on…. and…. on…. and….on….) A short history of molecular magnetism http://www.unizar.es/magmanet/magmanet-eu/index.php?/short_history_of_molecular_magnetism.html Molecular Magnetism Web: a gate to molelcular magnetiem (http:// www.molmag.de) thanks to Jürgen Schnack or is it Molecule-based Magnetism? (don’t trust Wikipedia….)
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Supported by the National Science Foundation
DMR-1202033 (MWM), DMR-1405439 (DRT),
DMR-1157490 (NHMFL), and the
UF Center for Tomorrow’s Materials (Today!)
Mark W. Meisel and Group Members (past and present)
Department of Physics and NHMFL, University of Florida
Long-standing collaboration with Daniel R. Talham and his Group
Department of Chemistry, University of Florida
“Molecular Magnetism”: What is it? What it is NOT!
or “What I wish I knew when I was in your seat….”
Start with a Definition: (but avoid blathering….. on…. and…. on…. and….on….)
A short history of molecular magnetismhttp://www.unizar.es/magmanet/magmanet-eu/index.php?/short_history_of_molecular_magnetism.html
Molecular Magnetism Web: a gate to molelcular magnetiem(http://www.molmag.de) thanks to Jürgen Schnack
or is it Molecule-based Magnetism? (don’t trust Wikipedia….)
Talham – Meisel Chemistry-Physics Group Retreat Aug. 2014
PAQ and MKP: PhD theses
(2015)
Switching magnetism with light above 77 K in a bistable coordination polymer heterostructureOlivia N. Risset, Tatiana V. Brinzari, Marcus K. Peprah,Pedro A. Quintero, Mark W. Meisel, Daniel R. Talham, preprint
Result 3: CoFe@CoCr-PBA core-shell nanoparticles (Change of Ingredient)Mechanism and Extent of Interface Strained Region
Light-Induced Changes in Magnetism in a Coordination Polymer Heterostructure … Olivia N. Risset, Pedro A. Quintero, et al., J. Am. Chem. Soc. 136 (2014) 15660.
Interfaced Strained Region (ISR) extends to about 25 nm in Shell.
Thickness of Shell influences Core and ISR and Domain rearrangement.
Ingredient 1: Photoactive Component: Spin-crossover (SCO)Hofmann-like framework (Change of Ingredient)
Light-Induced Excited Spin State Trapping = LIESST
Result 4: Films of SCO Fe-Pt and NiCr-PBA (Change of Ingredient)
Light-Induced Magnetization Changes in a Coordination Polymer Heterostructure …Corey R. Gros, Marcus K. Peprah, et al., J. Am. Chem. Soc. 136 (2014) 9846.
SCO Fe-Pt
Glass
NiCr-PBA
Result 5: Platelets of SCO Fe-Ni and NiCr-PBA (Change of Ingredient)
NiCr-PBA/Fe(azpy)[Ni(CN)4] : Marcus K. Peprah, Corey R. Gros, et al., in preparation
100 150 200 250 300
0.2
0.4
0.6
0.8
1.0
B = 100 G
Dark
Light
Ma
gn
etiz
atio
n [1
0-5 e
mu
G]
Temperature [K]
hν
CoFe@CrCrcore@shellnanoparticles
scale bar = 200 nm
Result 6: CoFe@CrCr-PBA nanoparticles (Change of Ingredient)
Switching magnetism with light above 77 K in a bistable coordination polymer heterostructureOlivia N. Risset, Tatiana V. Brinzari, Marcus K. Peprah,Pedro A. Quintero, Mark W. Meisel, Daniel R. Talham, preprint
Early attempts and hints: Elisabeth S. Knowles, Ph.D. thesis (2013)
Now Persistent Magnetism changes thermally compromised by CoFe-PBA electron relaxation.
Can the Interface Strained Region magnetic domains possess memory to CrCr-PBA TC = 220 K?
Co/Fe = 1.5
Co/Fe = 1.37
Co/Fe = 1.32
Co/Fe = 1.26
Co/Fe = 1.15
Shimamoto, Ohkoshi,
Sato, Hashimoto,
Inorg. Chem.
41 (2002) 678
350 K50 K
350 K5 K
5
0
High Spin
Low Spin
T vs. T
plots
NaxCoy[Fe(CN)6]z •nH2O
T vs. T
plots
Persistent Photocontrolled Magnetism (PPCM) inNanoscaled Heterostructures of Coordination Polymers[PBA = Prussian blue analogue]
A NiCr-PBA
B CoFe-PBA
A 100nm
B A
Reproducible TastyProperties!
Films: Pajerowski et al.,J. Am. Chem. Soc.132 (2010) 4058
Core@Shell: Dumont et al.,Inorg. Chem.
50 (2011) 4295
B C
Core@Shell: C = CoCr-PBARisset et al., JACS136 (2014) 15660
New Ingredient…same Tasty Properties!
Films with “spin crossover” Fe-Pt SCO / NiCr-PBAGros et al., J. Am. Chem. Soc. 136 (2014) 9846
Magnetic anisotropy in thin films of Prussian blue analogues
Phys. Rev. B 82 (2010) 214405
D.M. Pajerowski, J.E. Gardner, M.J. Andrus, S. Datta,A. Gomez, S.W. Kycia, S. Hill, D.R. Talham, M.W. Meisel
116 GHz
External Pressure tuning of the Magnetic Response in CoFe-PBA
Domain distortion in CrCr-PBA persists to Tc,which is Pressure Depedent.
100 150 200 250 300
0.00
0.02
0.04
0.06
0.08
0.10
0.12 September 2014
MP163: 109BC1-2 : CoFe@CrCr
White Light (no filter)
FC in 100 G, 0H = 100 G
Optical Presssure Probe 2.0
[ M
da
rk (
T)
- M
ligh
t(T
) ]
/ M
da
rk(T
= 3
00 K
)
Temperature (K)
P = 2.55 GPa
irradiation at 80 K
CrCr-PBA
TC Bulk
CoFe-PBA
TCTIST
Result 7: CoFe@CrCr-PBA nanoparticles (Light and Pressure) (Change of Environment)
Z. Mitróová et al., Acta Phys.Pol. A 133 (2008) 469
E.S. Knowles,Ph.D. thesis (2013)
10.4 Å10.3 Å
10.0 Å
APS – ANL dataunder analysis…A. Felts et al.
Laure Catala and Talal Mallah and coworkers
Small (< 30 mn) core@shellCoFe-PBA@NiCr-PBA:
Linkage Isomerism? (unpublished)
M. Verdaguer and G.S. Girolami (2004):“The solid Prussian blue analogues can also suffer from one or more of the following problems: (4) Linkage Isomersism”
Time, strain, interface… Irreversible / Reversible
“High pressure neutron scattering of the magnetoelasticNi-Cr Prussian blue analogue,” D. M. Pajerowski, S. E. Conklin, J. B. Leão, D. Phelan, L. W. Harriger, Phys. Rev. B 91, 094104 (2015)
(and untold story of route to T > 200 K)
High-TC core-shells?
50 100 150 200 250 3000
1
2
3
4
M (
10
-5 e
mu G
)
T (K)
dark
light
0H = 100 GA
0 50 100 150 200 250 3000.0
0.5
1.0
1.5
M (
10
-3 e
mu
G)
T (K)
CAB
dark
light
0H = 100 G
*heterogeneous (“chunks” of B in sample)?E. S. Knowles et al., unpublished.
CoFe-PBA
NiCr-PBA
CrCr-PBA
Diamagnetic FeII(LS, S = 0) – CN - CoIII(LS, S = 0)