Cu-based perovskite thin-film hybrids reveal unusual magnetic properties
Cu-based perovskite thin-film hybrids reveal unusual magnetic properties lead image
Perovskite materials and metal-organic frameworks (MOFs) are materials comprising different crystalline structures, combining the functionality of the former with the structural versatility of the latter to achieve intriguing ferromagnetic and electronic properties useful for a variety of applications. Aqeel et al. created a thin-film organic-inorganic perovskite hybrid that shares characteristics of both MOFs and perovskites in a single material.
The authors used a process known as the Langmuir-Blodgett (LB) technique to grow Cu-based hybrid (CuCl4) thin films. Unlike in the bulk material, CuCl4 (PEA)2 (where PEA is a phenylethylamine cation), the CuCl4 layers are coordinated by the same components on both sides in the LB films, featuring alternating hydrophilic (octadecyclamine, or ODA) and hydrophobic (methylamine, or MA) end groups. X-ray diffraction spectroscopy verified the thin-film structure.
Although the bulk material has demonstrated both ferromagnetism and ferroelectricity, the modified structure of the hybrid thin films, with long alkyl spacers rather than the shorter organic blocks in bulk crystals, leads to single ion anisotropy in Cu2+ ions and slightly reduces the ferromagnetic transition temperature. The hybrid thin films also demonstrate a large finite coercive field, apparently due to pinning of ferromagnetic domains in the antiferromagnetic second phase, which could enhance the memory functionality of these materials.
These differences in the magnetic properties of the hybrid thin films compared to bulk crystals arise from the structure of alternating ODA and MA component layers employed in the LB growth procedure. The work demonstrates new possibilities for further tailoring these CuCl4 films to give specific magnetic characteristics suitable for various applications.
Source: “Magnetic functionality of thin film perovskite hybrids,” by Aisha Aqeel, Naureen Akhtar, Alexey O. Polyakov, Petra Rudolf, and Thomas T. M. Palstra, APL Materials (2018). The article can be accessed at https://doi.org/10.1063/1.5042323 .
