Interacting Magnetic Phenomena in a Layered Cu–Based Halide Perovskite Heterostructure

Layered magnetic materials, wherein magnetic properties in a two-dimensional (2D) sheet can be altered or augmented by magnetic or electronic effects in neighboring sheets, hold great promise for applications in magnetic data storage and spintronic device fabrication. Often these materials showcase unusual emergent properties, inaccessible in the monolayers by themselves. Due to their diverse applications and ability to host exotic physical properties, stacked 2D magnetic materials have received increasing attention. However, most such heterostructures are built one sheet at a time, using layer–by–layer deposition techniques or mechanical exfoliation and restacking, which preclude scalable syntheses.

Solution-state self-assembly techniques are an attractive alternative to exfoliation because they are simple, economical, and require minimal equipment or energy usage. Halide perovskite heterostructures, first reported in 2021, can be prepared as large single crystals or films using solution state self–assembly techniques. These materials use a bifunctional molecule to tether the 2D perovskite lattice to another 2D inorganic lattice between the perovskite sheets. It has been possible to target novel heterostructure compositions by using different bifunctional molecules. I will discuss the synthesis, structure, and magnetic properties of a new halide perovskite heterostructure composed of two different magnetic layers. Using dc and ac magnetometry, electron paramagnetic resonance, and heat capacity measurements, we have studied the temperature-dependent magnetic interactions within the individual layers and between the two layers, revealing a sequence of magnetic ordering steps. I will describe our understanding of the low-temperature spin ordering in the heterostructure and discuss how we can synthetically finetune these spin interactions. The ability to tune the magnetic ground state by altering interlayer interactions in a self–assembling layered heterostructure has exciting implications for the future development of halide perovskite heterostructures for fundamental physics studies and spintronic device applications.