Toward Magneto‐Optical Cryogenic Thermometers with High Sensitivity: A Magnetic Circular Dichroism Based Thermometric Approach

Abstract

Remote temperature probing at the cryogenic range is of utmost importance for the advancement of future quantum technologies. Despite the notable achievements in luminescent thermometers, accurately measuring temperatures below 10 K remains a challenging endeavor. In this study, we propose a novel magneto‐optical thermometric approach based on the magnetic‐circular dichroism (MCD) technique, which offers unprecedented capabilities for meticulous temperature variation analysis at cryogenic temperatures. The inherent temperature sensitivity of the MCD C‐term, in conjunction with both positive and negative signals, enables highly sensitive magneto‐optical temperature probing. Additionally, a groundbreaking relative thermal sensitivity value of 95.3% K‐1 at 2.54 K can be achieved using a mononuclear lanthanide complex, [[Ho(acac)3(phen)], in the presence of a 0.25 T applied magnetic field and using a combination of multiparametric thermal read‐out with multiple regression. These results unequivocally demonstrate the viability and effectiveness of our methodology for cryogenic temperature sensing.

Optical Phenomena in Molecule-Based Magnetic Materials

“…Moreover, optical thermometry based on the magnetic circular dichroism effect was recently presented for lanthanide(III) complexes. 1011 This uncovers outstanding potential in the development of advanced SMM-based magneto-optical systems further exploring MCD, MChD, as well as CPL effects in molecule-based magnetic materials.…”

“…For instance, such attempts were made using Yb 3+ ions combined with 3-trifluoroacetyl-(+)-camphorato (facam) and bis­(1,10-phenantro­[5,6b])­tetrathiafulvalene ligands or for the series of the Dy­(III)-based complexes with BINOL-functionalized (BINOL = ([1,1′-binaphthalene]-2,2′-diol)) bisphosphate ligands. , Such examples, combining both structural chirality/polarity, luminescence, and magnetic properties, were gathered and discussed in section . Moreover, optical thermometry based on the magnetic circular dichroism effect was recently presented for lanthanide­(III) complexes . This uncovers outstanding potential in the development of advanced SMM-based magneto-optical systems further exploring MCD, MChD, as well as CPL effects in molecule-based magnetic materials.…”

Dual-signalled magneto-optical barcodes with lanthanide-based molecular cluster-aggregates

“…In our recent work related to magneto-optical thermometers based on MCD, 39 we discussed about some advantages, disadvantages, and challenges on using MCD spectroscopy for applications. The same challenges reported there are valid for the magneto-optical barcodes reported in this work, and we foreseen that further works on potential applications for MCD spectroscopy will help us to tackle these challenges.…”