Effect of the change in the interface structure of Pd(100)/SrTiO3 for quantum-well induced ferromagnetism

TL;DR

This study explores how interface structural changes, caused by SrTiO3's phase transition, affect quantum-well induced ferromagnetism in Pd(100) ultrathin films, revealing that cracks weaken magnetic properties.

Contribution

It demonstrates that interface cracks from SrTiO3 phase transition diminish quantum-well ferromagnetism in Pd(100) films, highlighting the importance of interface integrity.

Findings

Cracks induced by SrTiO3 phase transition alter magnetic moment dependence on film thickness.

Repeated temperature cycling reduces ferromagnetism due to crack accumulation.

Lower crystallinity at the interface negatively impacts quantum-well induced ferromagnetism.

Abstract

Pd(100) ultrathin films show ferromagnetism induced by the confinement of electrons in the film, i.e., the quantum-well mechanism. In this study, we investigate the effect of the change in the interface structure between a Pd film and SrTiO3 substrate on quantum-well induced ferromagnetism using the structural phase transition of SrTiO3. During repeated measurement of temperature- dependent magnetization of the Pd/SrTiO3 system, cracks were induced in the Pd overlayer near the interface region by the structural phase transition of SrTiO3, thereby changing the film-thickness dependence of the magnetic moment. This is explained by the concept that as the magnetic moment in Pd(100) changed, so too did the thickness of the quantum-well. In addition, we observed that the ferromagnetism in the Pd(100) disappeared with the accumulation of cracks due to the repetition of the temperature cycle through the phase-transition temperature. This suggests that lowering the crystallinity of the interface structure by producing a large number of cracks has a negative effect on quantum-well induced ferromagnetism.