Multiferroic rhodium clusters.
Simultaneous magnetic and electric deflection measurements of rhodium clusters (Rh(N), 6 ≤ N ≤ 40) reveal ferromagnetism and ferroelectricity at low temperatures, while neither property exists in the bulk metal. Temperature-independent magnetic moments (up to 1 μ(B) per atom) are observed, and superparamagnetic blocking temperatures up to 20 K. Ferroelectric dipole moments on the order of 1D with transition temperatures up to 30 K are observed. Ferromagnetism and ferroelectricity coexist in rhodium clusters in the measured size range, with size-dependent variations in the transition temperatures that tend to be anticorrelated in the range n = 6-25. Both effects diminish with size and essentially vanish at N = 40. The ferroelectric properties suggest a Jahn-Teller ground state. These experiments represent the first example of multiferroic behavior in pure metal clusters.
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Lei
L
Ma
Cameron University, Lawton, Oklahoma 73505, USA.
Ramiro
R
Moro
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
John
J
Bowlan
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Walt A
WA
de Heer
Andrei
A
Kirilyuk