Magnetism of Mixed Prussian Blue Analogs and Low Dimensional Frustated Systems

Mark W. Meisel (Physics, University of Florida) DMR-0701400

The ability to purposefully tune magnetic properties of synthetic materials has motivated progress in the area of molecule-based magnets.

Our studies show bulk powders of a Prussian blue analog, NaαNi1-xCox[Fe(CN)6]β·nH2O, possess

photoinduced magnetism that can be either positive or negative (as shown at right), depending upon the cobalt fraction x, the applied magnetic field, and the temperature. The underlying mechanism of this phenomena is readily modeled [see (a) and (b)] and, thus, allows the photo-controlled magnetic properties to be designed by a choice of the transition metal ions and their concentrations.

These developments are now being extended to thin films and nanoparticles, and the magnetic transition temperatures are being shifted to technologically interesting temperatures near 77 K.

D.M. Pajerowski, J.E. Gardner, D.R. Talham, M.W. Meisel, J. Am. Chem. Soc., web publication: August 24, 2009, doi:10.1021/ja9012672.

Spair= 0 Spair=-1

Spair= 0 Spair=+1

(a)

(b)

Ni Co Fe

Magnetism of Mixed Prussian Blue Analogs and Low Dimensional Frustated Systems

Mark W. Meisel (Physics, University of Florida) DMR-0701400

This interdisciplinary research builds upon our long-standing intramural (UF Physics-Chemistry and NHMFL High-B/T Lab) and international (Centre of Low Temperature Physics, Košice, Slovakia) and extends these links (e.g. High Magnetic Field Lab (HLD), Dresden, Germany).

The training of graduate and undergraduate students involves hands-on laboratory experiences and visits to national (e.g. SNS-ORNL and NHMFL) and international facilities and meetings.

The PI embraces Outreach Activities and his recent work focuses on K-8 teacher/student experiences involving “matter”. Elements of his work were used by the Florida PROMiSE Progam, and the PI is a developer and faculty participant.

0 2 4 6 8 100

1

2

3

Spin gap

T (

K)

B (T)

Paramagnet

V, AV

V+AV

V+AV

Soft spin modes

Out of plane ferromagnetic correlations

SRO

Department of PhysicsDepartment of Chemistry

Meisel Group “Leatherheads” Summer 2009: (left to right) Carrie Schindler, REU, Univ. Evansville; Elisabeth Knowles, UF grad student; Mark Meisel, PI; Daniel Pajerowski, UF grad student, Nick Lavini, REU, Manhattan College.

Other NSF grants providing collaborative support:Daniel R. Talham, UF Chem (DMR-0453362), UF Physics Summer REU Program (DMR-0851707), NHMFL (DMR-0654118).

Temperature (T) versus Magentic Field (B): phase diagram of a novel two-dimensional

magnet Cu(tn)Cl2, see A. Orendáčová et al., arXiv:0906.3181 and to be published.

Model of Chemical Reactions: Cookie Sheet & Poker Chips!Meisel leads discussion during Duval (Jacksonville) PROMiSE K-8 Teachers Outreach Program.