Collapsing cycloidal structures in the magnetic phase diagram of erbium

• Published in: Physical review. B, Condensed matter Condensed matter, 1994-08, Vol.50 (5), p.3085-3091
• Main Authors: Jehan, DA, McMorrow, DF, Simpson, JA, Cowley, RA, Swaddling, PP, Clausen, KN
• Format: Article
• Language: English
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/physrevb.50.3085

The magnetic structure of Er with a magnetic field applied in the hexagonal basal plane has been studied using a combination of experimental techniques and mean-field modeling. From neutron-scattering and magnetization measurements, phase diagrams are constructed. At temperatures above approx20K, the application of a field is found to favor cycloidal structures with modulation wave vectors of q sub c =(6/23)c exp * , (4/15)c exp * , and (2 /7)c exp * . For fields above approx40 kOe, the (2/7) structure dominates the phase diagram. From a detailed study of this most stable cycloid, it was determined how it distorts as the field is increased. In low fields, there is a spin reorientation, so that the plane of the cycloid becomes perpendicular to the applied field, while in larger fields, the cycloid collapses through a series of fanlike structures. At lower temperatures, as the field is increased there is a first-order transition at approx20 kOe from a cone to a fan in the a-c plane.