Topology and spin dynamics in magnetic molecules

Abstract

We investigate the role of topology and distortions in the quantum dynamics of magnetic molecules, using a cyclic spin system as reference. We consider three variants of antiferromagnetic molecular ring, i.e. Cr${}_8$, Cr${}_7$Zn and Cr${}_7$Ni, characterized by low lying states with different total spin $S$. We theoretically and experimentally study the low-temperature behavior of the magnetic torque as a function of the applied magnetic field. Near level crossings, this observable selectively probes quantum fluctuations of the total spin (''$S$ mixing") induced by lowering of the ideal ring symmetry. We show that while a typical distortion of a model molecular structure is very ineffective in opening new $S$-mixing channels, the spin topology is a major ingredient to control the degree of $S$ mixing. This conclusion is further substantiated by low-temperature heat capacity measurements.

5 pages, 4 figures

References in corpus (7)

• Quantum Computing in Molecular Magnets
• Molecular engineering of antiferromagnetic rings for quantum computation
• Quantum computing with antiferromagnetic spin clusters
• Spin dynamics of heterometallic Cr7M wheels (M = Mn, Zn, Ni) probed by inelastic neutron scattering
• S-mixing and quantum tunneling of the magnetization in molecular nanomagnets
• Quantum-magneto oscillations in a supramolecular Mn(II)-[3 x 3] grid
• Macroscopic evidence of quantum coherent oscillations of the total spin in the Mn-[3x3] molecular nanomagnet

Cited by in corpus (10)

• Magnetothermal properties of molecule-based materials
• Magnetic Cluster Excitations
• Spin dynamics of molecular nanomagnets fully unraveled by four-dimensional inelastic neutron scattering
• Quantum Phase Interference and Neel-Vector Tunneling in Antiferromagnetic Molecular Wheels
• Many-body models for molecular nanomagnets
• Resonant photon absorption and hole burning in Cr7Ni antiferromagnetic rings
• Spin Entanglement in supramolecular structures
• Influence of intermolecular interactions on magnetic observables
• Spin anisotropy effects in dimer single molecule magnets
• Field-induced level crossings in spin clusters: Thermodynamics and magneto-elastic instability