Abstract
Neutron diffraction studies on polycrystalline and single-crystal specimens of thulium have been made at temperatures ranging from room temperature to 1.3°K. The results are interpreted by means of a method which exhibits explicitly the Fourier components of the distribution of magnetic moments on the lattice sites. At about 56°K, the Néel temperature, a simple oscillating -component-type antiferromagnetic structure is developed. At approximately 40°K, nonzero Fourier coefficients of overtones of the fundamental observed at higher temperatures are first detected. At 4.2°K the magnetic structure of thulium is a type of antiphase domain structure in which several layers of moments parallel to the direction are followed by several layers in which the moments are oppositely directed. The sequence in thulium is -4, +3, -4, +3,... etc. Each atom has, within the precision of the experiments, an ordered moment of , and the ferrimagnetic structure has a net moment, parallel to the axis, of per atom. The fundamental period of the modulation remains constant over the whole range of temperatures at a value corresponding to periods. In the course of this study the scattering amplitude of thulium was determined to be cm.
- Received 24 January 1962
DOI:https://doi.org/10.1103/PhysRev.126.1672
©1962 American Physical Society