Magnetic susceptibility of EuTe/PbTe Heisenberg superlattices: experimental and theoretical studies

TL;DR

This study investigates the magnetic susceptibility of EuTe/PbTe superlattices, revealing anisotropic behavior and phase transitions, with experimental measurements supported by theoretical models highlighting the role of dipolar interactions.

Contribution

It provides new experimental data and theoretical analysis on magnetic phase transitions and anisotropy in EuTe/PbTe superlattices, emphasizing the stabilizing role of dipolar interactions.

Findings

Strong low-temperature anisotropy observed

Magnetic phase transition confirmed in thicker samples

Dipolar interactions stabilize antiferromagnetic order

Abstract

We report results on the temperature dependence of the susceptibilities of a set of MBE-grown short-period EuTe/PbTe antiferromagnetic superlattices having different EuTe layer thicknesses. In-plane and orthogonal susceptibilities have been measured and display a strong anisotropy at low temperature, confirming the occurrence of a magnetic phase transition in the thicker samples, as seen also in neutron diffraction studies. We suggest that dipolar interactions stabilize antiferromagnetic long-range order in an otherwise isotropic system and we present numerical and analytical results for the low-temperature orthogonal susceptibility.