Chemical Strain Engineering of Magnetism in Oxide Thin Films

Transition metal oxides having a perovskite structure form a wide and technologically
important class of compounds. In these systems, ferroelectric, ferromagnetic,
ferroelastic, or even orbital and charge orderings can develop and
eventually coexist. These orderings can be tuned by external electric, magnetic,
or stress field, and the cross-couplings between them enable important
multifunctional properties, such as piezoelectricity, magneto-electricity, or
magneto-elasticity. Recently, it has been proposed that additional to typical
fields, the chemical potential that controls the concentration of ion vacancies
in these systems may reveal an efficient alternative parameter to further tune
their properties and achieve new functionalities. In this study, concretizing
this proposal, the authors show that the control of the content of oxygen
vacancies in perovskite thin films can indeed be used to tune their magnetic
properties. Growing PrVO3 thin films epitaxially on an SrTiO3 substrate, the
authors reveal a concrete pathway to achieve this effect. The authors demonstrate
that monitoring the concentration of oxygen vacancies through the
oxygen partial pressure or the growth temperature can produce a substantial
macroscopic tensile strain of a few percent. In turn, this strain affects the
exchange interactions, producing a nontrivial evolution of Néel temperature
in a range of 30 K.