Inelastic neutron scattering and frequency-domain magnetic resonance studies ofS=4andS=12

Abstract

A & Tejada, J 2010, 'Inelastic neutron scattering and frequency-domain magnetic resonance studies of S=4 and S=12 Mn-6 single-molecule magnets ' Physical Review B, vol. 81, no. 17, 174420, pp. - General rightsCopyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policyThe University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact openaccess@ed.ac.uk providing details, and we will remove access to the work immediately and investigate your claim. We investigate the magnetic properties of three Mn 6 single-molecule magnets by means of inelastic neutron scattering and frequency domain magnetic resonance spectroscopy. The experimental data reveal that small structural distortions of the molecular geometry produce a significant effect on the energy-level diagram and therefore on the magnetic properties of the molecule. We show that the giant spin model completely fails to describe the spin-level structure of the ground spin multiplets. We analyze theoretically the spin Hamiltonian for the low-spin Mn 6 molecule ͑S =4͒ and we show that the excited S multiplets play a key role in determining the effective energy barrier for the magnetization reversal, in analogy to what was previously found for the two high spin Mn 6 ͑S =12͒ molecules ͓S. Carretta et al., Phys. Rev. Lett. 100, 157203 ͑2008͔͒.

Environmental Influence on the Single-Molecule Magnet Behavior of [MnIII6CrIII]3+: Molecular Symmetry versus Solid-State Effects

“…3−5 However, this is merely a rough approximation, implying that there is no significant mixing of M S levels of excited spin states with those of the ground-state multiplet, which holds true in the limit of strong exchange (J ≫ D). 191,192 Another important aspect is the origin of D S t . As anisotropic and dipolar interactions usually provide only minor contributions to the anisotropy of the ground state, the main source of D S t is the projection of the single-site anisotropies D i onto the spin ground state.…”

Relieving frustration: The case of antiferromagnetic Mn3molecular triangles

“…However, magnetic and electron paramagnetic resonance (EPR) [19,27,30,33]. As we demonstrate in the present study, this can be attributed to the spin frustration inherent to AF triangular systems [34].…”

“…However, in spite of exhaustive efforts, it has not been possible to obtain detailed spectroscopic information concerning the molecular anisotropy for any of the AF Mn 3 III molecules until recently [17,18,32]. This has prevented detailed comparisons between AF and FM complexes along the lines of recent work reported for Mn 6 III [19,27,30,33]. As we demonstrate in the present study, this can be attributed to the spin frustration inherent to AF triangular systems [34].…”

“…This motivated efforts to extend such strategies to larger molecules containing triangular [Mn 3 III -(μ 3 -oxo)] units, resulting in a series of FM Mn 6 III SMMs, which currently hold the record for both blocking temperature and anisotropy barrier for any transition metal-based SMM [22][23][24][25][26][27].…”

Frequency domain magnetic resonance and magnetic circular dichroism studies on Ni4 cubane molecular nanomagnets: A magnetic anisotropy investigation

“…The absence of a magnetic field in a FDMRS experiment also simplifies the simulation of the spectra and more sophisticated experiments, including the observation of the relaxation of the magnetisation and of the QTM, can be performed [28,29]. This highly versatile technique has been exploited in studies on a number of mononuclear and polynuclear complexes including [Mn 9 O 7 (O 2 CCH 3 ) 11 (thme)(py) 3 6 [O 2 CPh(Me) 2 ] 2 (EtOH) 6 [34].…”