Epitaxial growth and magnetic phase transitions in non-centrosymmetric EuPdSi$_3$ thin films

TL;DR

This study reports the successful epitaxial growth of EuPdSi$_3$ thin films, revealing magnetic phase transitions and the potential for stabilizing chiral spin textures due to non-centrosymmetric structure.

Contribution

First demonstration of epitaxial EuPdSi$_3$ thin films with detailed analysis of magnetic phases and structural properties.

Findings

Epitaxial EuPdSi$_3$ films confirmed with X-ray diffraction.

Magnetic phase transitions observed at 19 K and 15 K.

Magnetic ground state sensitive to field orientation.

Abstract

Non-centrosymmetric magnetic materials are a promising platform for stabilizing chiral spin textures, such as skyrmions and cycloidal magnetic states. This is particularly true in epitaxial thin film geometries, where strain and interface effects offer additional control. Herein, we report on the first epitaxial thin films of EuPdSi$_3$ grown by molecular beam epitaxy on MgO(001). X-ray diffraction confirms an epitaxial relationship of tetragonal EuPdSi$_3$ in the BaNiSn$_3$ structure with out-of-plane c-axis orientation and parallel in-plane a-axes. Hard x-ray photoelectron spectroscopy reveals a stable Eu valence of 2.0, yielding a large magnetic moment of approximately 7 $\mu_B$ per Eu atom in accordance with Hund's rule. Owing to the non-centrosymmetric crystal structure, non-collinear magnetic states such as N\'eel-type skyrmions and cycloidal phases are allowed by symmetry. Electronic transport measurements reveal two magnetic phase transitions at 19 K and 15 K in zero applied field. Under magnetic fields applied along the crystallographic [100] and [001] directions, distinct temperature dependent magnetic phases emerge, demonstrating the sensitivity of the magnetic ground state to field orientation in epitaxial EuPdSi$_3$ thin films.