Erbium spin waves

The magnetic term in the heat capacity is what would be expected from the ferromagnetic spiral (i.e. the cone) structure of erbium (Kaplan 1961) and has been supported by the discovery of a linear spin-wave dispersion law along the c-axis in neutron scattering experiments (Nicklow et al. 1971). 

EDMR has allowed several different unusual experiments. For example, neutral arsenic dopants interacting with a 2D electron gas have been studied with continuous-wave EDMR at 9.7 GHz and 94 GHz. The Anderson-Mott transition between conduction by sequential tunneling through isolated dopant atoms, and conduction through thermally activated impurity Hubbard bands has been studied in arrays of a few arsenic dopant atoms in a silicon transistor. Single erbium spins with resolved hyperfine structure have been electrically detected after resonant optical excitation. The use of the valley degree of freedom has been eonsidered with dopants in silicon both experimentally and theoretically. The quantum confinement due to silicon nanowires may inerease the temperatures where silicon donor quantum devices ean operate. ... 

Erbium. The easy direction in Er is the c-axis, and below the second-order Neel transition (Tn = 85 K), the moments order in a longitudinal sine-wave structure. As the temperature is lowered the sine squares up. Aroimd Tb = 52 K, a basal plane component begins to order, leading to a helical AFM structure. Finally, at 7c = 20K a first-order transition into a steep cone (opening angle 30 ) FM spin structure takes place. Several (first-order) spin-slip transitions occur in the helical AFM phase. 

Erbium exhibits a complex magnetic behaviour, with at least four obserrable characteristic temperatures below rN = 85K, the moments order in a sinusoidal c-axis modulated (CAM) structure at rH=54K, there appears a component perpendicular to the c-axis resulting in a helicoidal structure this intermediate phase exhibits a sequence of lock-in transitions of commensurate phases (spin-slip structures) with wave vectors fm = f, 4 observed by iX-ray scattering (Gibbs et al. 1986), the... 

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