Multiferroic Rhodium Clusters

Abstract

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.

Electronic structure and thermochemical properties of neutral and anionic rhodium clusters Rhn, n=2–13. Evolution of structures and stabilities of binary clusters RhmM (M=Fe, Co, Ni; m=1–6)

“…In a previous study, Jinlong and coworkers [48] revealed that the lowest-energy geometry of Rh 12 is the distorted icosahedron (Rh-12-D). However, our findings indicate that Rh-12-D in both triplet and quintet state is quite unstable being 57.1 and 57.9 kcal/mol above the most stable structure Rh-12-A (D 4h , 9 A 1g ) which can be viewed as a double cube. The same structure Rh-12-A also found for various multiplicites namely triplet, septet, and 11tet are higher in energy.…”

“…The last isomer is a capped cube structure Rh-9-E (C 4v ) lying 11.4 kcal/mol higher in energy than the ground state Rh-9-A. It is interesting that several quasi-degenerate states compete for the ground state of Rh 9 , that is, the Rh-9-A with 15 A and 17 A and the Rh-9-B (C 1 , 15 A). The relative energies of other electronic states are listed in Table 3.…”

“…For Rh clusters large magnetic moments have been reported by Cox [7,8], experimental results in these reports indicated that small rhodium clusters with less than 60 atoms have non-zero magnetic moments. Recently, the investigation on the multiferroic behavior of Rh n clusters (n = 6-40) carried out by Ma [9] presented that ferromagnetism and ferroelectricity co-occur in small Rh clusters and decrease consistently with increasing size and basically vanish for n = 40. The study of magnetism in clusters is a two-step process, namely the identification of the lowest energy geometrical structures and the determination of the respective electronic properties.…”

Amplification of Relativistic Electron Bunches by Acceleration in Laser Fields

“…This prerequisite can be met if an intense and linearly polarized laser pulse interacts with a solid and leads to the emission of electron bunches within a half cycle of an optical laser field. In particular, the investigation of such kind of laser created dense electron bunches is motivated by the search for a relativistic electron mirror upon which a second laser pulse could be reflected and then is upshifted in frequency due to the relativistic Doppler effect [11,12,[14][15][16][17]. The efficiency of the relativistic backscattering process is dependent on a high density and narrow spectral distribution of the electron layer.…”

Review of quarkonium production: status and prospects

“…In Refs. [74,75,76], the authors employed the color glass condensate framework [77,78,79,80] to describe J/ψ hadroproduction for p T comparable to, or even smaller than, the J/ψ mass, where the short-distance process is sensitive to the proton structure at very small Bjorken x. Based on the long-distance matrix elements determined in Ref.…”