Hydrogen adsorption and magnetic behavior ofFenandConclusters: Controlling the magnetic moment and anisotropy one atom at a time

Abstract

Theoretical studies to investigate the effect of H absorption on the magnetic moment of small Fe n and Co n clusters have been carried out using gradient corrected density-functional approach. Our studies on clusters containing up to four transition metal and 2 H atoms show that the successive addition of H atoms can lead to monotonic or oscillatory change from the free cluster magnetic moment. A detailed analysis of the density of electronic states shows that the variations in the magnetic moment can be related to the location of the lowest unoccupied molecular orbital in the parent cluster. It is shown that the addition of hydrogen can substantially change the magnetic anisotropy. In particular Co 3 H 2 is shown to exhibit magnetic anisotropy that is higher than any of the known anisotropies in the molecular nanomagnets.

Controlling the Spin of Co Atoms on Pt(111) by Hydrogen Adsorption

“…[20], no higher energy spin-excitation between m ¼ 1=2 → m ¼ 3=2 were observed; however, they might be obscured by the vibrational features. For a free CoH 2 in a bent geometry, two spin states S ¼ 1=2 and S ¼ 3=2 have been predicted, they exhibit H-Co-H bond angles of 90 and 65 degrees, respectively [17,18]. In the free molecule the first is the ground state.…”

“…These calculations reveal a significant change of the magnetic properties through hydrogenation, with a clear tendency of decreasing spin with increasing number of H atoms [17][18][19]. This results from the antiparallel spin alignment between metal and H. In particular, for the case of Co, the spin S ¼ 3=2 of the free atom is reduced to 1 and 1=2 upon the adsorption of one and two hydrogen atoms, respectively [17][18][19].…”

“…These calculations reveal a significant change of the magnetic properties through hydrogenation, with a clear tendency of decreasing spin with increasing number of H atoms [17][18][19]. This results from the antiparallel spin alignment between metal and H. In particular, for the case of Co, the spin S ¼ 3=2 of the free atom is reduced to 1 and 1=2 upon the adsorption of one and two hydrogen atoms, respectively [17][18][19].The effect of hydrogen adsorption on the spin of surfaceadsorbed magnetic atoms is largely unknown. Hints that the spin possibly changes upon H adsorption can be inferred from the H-induced appearance [14] or disappearance [13,15] of the Kondo effect.…”

The Ground State Structures and Magnetic Properties of ZrnNi (n=1-9) Clusters from First Principles Calculation

“…Atomic cluster shows new physical phenomena due to quantum size effect, macroscopic quantum tunneling effect and surface effect, which make it fit for the design and synthesis of new materials, thus, atom cluster attract the attention of many theoretical and experimental workers in recent 30 years [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Electronic structure, stability and magnetic properties of small M1–4(M = Fe, Co, Ni) clusters encapsulated inside a (BN)48 cage

“…Most theoretical calculations for Fe 2 predicted the 7 u state was the ground state [22][23][24][25][26]. Gutsev et al [22] and Yu et al [23] determined there were 10(Fe 3 ) unpaired electrons in the neutral ground state.…”