Growth diagram and magnetic properties of hexagonal LuFe$_2$O$_4$ thin films

TL;DR

This study maps the growth conditions for LuFe₂O₄ thin films on MgO substrates, investigates their magnetic properties, and explains the superparamagnetism observed through surface thermochemistry and structural defects.

Contribution

It provides a detailed growth diagram for LuFe₂O₄ films and offers insights into their magnetic behavior and underlying growth mechanisms.

Findings

LuFe₂O₄ phase is only stable within specific temperature and oxygen pressure ranges.

Superparamagnetism observed in LuFe₂O₄ films due to impurities and defects.

Growth mechanism explained via surface thermochemistry.

Abstract

A growth diagram of Lu-Fe-O compounds on MgO (111) substrates using pulsed laser deposition is constructed based on extensive growth experiments. The LuFe$_2$O$_4$ phase can only be grown in a small range of temperature and O$_2$ pressure conditions. An understanding of the growth mechanism of Lu-Fe-O compound films is offered in terms of the thermochemistry at the surface. Superparamagnetism is observed in LuFe$_2$O$_4$ film and is explained in terms of the effect of the impurity h-LuFeO$_3$ phase and structural defects .