Diamagnetic-like response from localized heating of a paramagnetic material*

In the study of material properties out-of-equilibrium, the non-equilibrium steady states (NESS) induced by electric current are an appealing research direction where unconventional states may emerge. Especially, the effects of steady electric current on metal-insulator transitions and magnetic transitions in strongly-correlated systems are attracting recent interests. However, the unavoidable Joule heating caused by flowing current calls for the development of new measurement protocols, with particular attention to the physical properties of the background materials involved. Here, we demonstrate that localized heating can give rise to a large, spurious diamagnetic-like signal [1]. This occurs due to the local reduction of the background magnetization caused by the heated sample, provided the background material has a Curie-like susceptibility. Our experimental results, along with numerical calculations, constitute an important building block for performing accurate magnetic measurements under the flow of electric current.
[1] G. Mattoni et al., Appl. Phys. Lett. 116, 172405 (2020); doi: 10.1063/5.0006098.