Double-q Magnetic Structure and Spin-Block Metamagnetism of ErRu₂Si₂ as Studied by Neutron Diffraction

Abstract

Neutron diffraction experiments with use of horizontal magnetic field have been carried out to study the magnetic structure of the ground state and the origin of the metamagnetism of the compound ErRu₂Si₂. Combination of the results of the previous magnetization measurements and of the present intensity measurements of several satellite reflections from a single-crystalline sample in null field leads to a conclusion that the ground-state magnetic structure consists of a double-q superimposed structure of long-period transverse modulations. The metamagnetism together with the response of the satellite reflections to magnetic field have been satisfactorily explained on the basis of this double-q structure under assumptions of strong Ising anisotropy and persisting molecular field.