title: Possible Room-Temperature Ferromagnetism in Self-Assembled Ensembles of Paramagnetic and Diamagnetic Molecular Semiconductors.
abstract: Owing to long spin-relaxation time and chemically customizable physical properties, molecule-based semiconductor materials like metal-phthalocyanines offer promising alternatives to conventional dilute magnetic semiconductors/oxides (DMSs/DMOs) to achieve room-temperature (RT) ferromagnetism. However, air-stable molecule-based materials exhibiting both semiconductivity and magnetic-order at RT have so far remained elusive. We present here the concept of supramolecular arrangement to accomplish possibly RT ferromagnetism. Specifically, we observe a clear hysteresis-loop (Hc≈ 120 Oe) at 300 K in the magnetization versus field (M-H) plot of the self-assembled ensembles of diamagnetic Zn-phthalocyanine having peripheral F atoms (ZnFPc; S = 0) and paramagnetic Fe-phthalocyanine having peripehral H atoms (FePc; S = 1). Tauc plot of the self-assembled FePc···ZnFPc ensembles showed an optical band gap of ∼1.05 eV and temperature-dependent current-voltage (I-V) studies suggest semiconducting characteristics in the material. Using DFT+U quantum-chemical calculations, we reveal the origin of such unusual ferromagnetic exchange-interaction in the supramolecular FePc···ZnFPc system.
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER) , Pune 411008, India.
authors.forename: Barun
authors.initials: B
authors.lastname: Dhara
authors.affiliation: Department of Physics, National Institute of Technology Karnataka (NITK) , Mangalore 575 025, India.
authors.forename: Kartick
authors.initials: K
authors.lastname: Tarafder
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER) , Pune 411008, India.
authors.forename: Plawan K
authors.initials: PK
authors.lastname: Jha
authors.affiliation: Department of Physics, Indian Institute of Science Education and Research (IISER) , Pune 411008, India.
authors.forename: Soumendra N
authors.initials: SN
authors.lastname: Panja
authors.affiliation: Department of Physics, Indian Institute of Science Education and Research (IISER) , Pune 411008, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Nair
authors.affiliation: Department of Physics and Astronomy, Uppsala University , Box 516, S-751 20 Uppsala, Sweden.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Oppeneer
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER) , Pune 411008, India.
authors.forename: Nirmalya
authors.identifier: http://orcid.org/0000-0002-7916-7334
authors.initials: N
authors.lastname: Ballav