Spin single lanthanide ions

Control of the Magnetic Anisotropy of Lanthanide Ions Chemical Design of Spin Qubits 7.3.2.1 Mononuclear Single Molecule Magnets... 

Lanthanide ions offer narrow EPR line widths, and the first successful device (Scovil et al. 1957) made use of three levels of the trivalent gadolinium ion, 87/2, in lanthanum ethylsulphate. A 90 mg single crystal containing 0.5%Gd, and 0.2% Ce to obtain suitable spin-lattice relaxation rates (Feher and Scovil 1957), was... 

Upon rotating the magnetic field in the (011) plane of a single crystal of LaS doped with 2000 ppm Er, Bloch et al. (1982) found an angular-dependent linewidth. They assumed a T7 ground state of Er followed by a Tg excited state. Internal strains of Fs type are coupled to the lanthanide ions via magnetoelastic effects. The spin Hamiltonian... 

The basic requirement for EPR is that the sample to be studied contain unpaired electron spins. Lanthanide ions, having incompletely filled 4f shells, certainly meet this requirement, and when present in sufficiently low concentrations (typically less than 0.1%) they may be regarded as not interacting with each other. Under these circumstances the single ion approximation normally applies. 

Spectra of trivalent lanthanide ions are much more complicated than those of transition metal ions, which show only a few broad bands. Because the partially filled 4f shell is shielded by the filled 5s and 5p orbitals, the lanthanide ion is only moderately influenced by its environment. Therefore it behaves to a large extent like a free ion. The crystal field is a weak perturbation compared to the electron repulsion and spin-orbit coupling. The optical absorption spectra of 4f systems in single crystals are similar to atomic spectra in the sense that they may sometimes show a large number of very narrow lines. The abundance of lines in the spectra of trivalent lanthanide ions has puzzled earlier spectroscopists. It was J. Becquerel (Becquerel 1907, Becquerel and Kamerlingh Onnes... 

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