Molecular magnetic hysteresis at 60 kelvin in dysprosocenium

Abstract

Lanthanides have been investigated extensively for potential applications in quantum information processing and high-density data storage at the molecular and atomic scale. Experimental achievements include reading and manipulating single nuclear spins, exploiting atomic clock transitions for robust qubits and, most recently, magnetic data storage in single atoms. Single-molecule magnets exhibit magnetic hysteresis of molecular origin-a magnetic memory effect and a prerequisite of data storage-and so far lanthanide examples have exhibited this phenomenon at the highest temperatures. However, in the nearly 25 years since the discovery of single-molecule magnets, hysteresis temperatures have increased from 4 kelvin to only about 14 kelvin using a consistent magnetic field sweep rate of about 20 oersted per second, although higher temperatures have been achieved by using very fast sweep rates (for example, 30 kelvin with 200 oersted per second). Here we report a hexa-tert-butyldysprosocenium complex-[Dy(Cp)][B(CF)], with Cp = {CHBu-1,2,4} and Bu = C(CH)-which exhibits magnetic hysteresis at temperatures of up to 60 kelvin at a sweep rate of 22 oersted per second. We observe a clear change in the relaxation dynamics at this temperature, which persists in magnetically diluted samples, suggesting that the origin of the hysteresis is the localized metal-ligand vibrational modes that are unique to dysprosocenium. Ab initio calculations of spin dynamics demonstrate that magnetic relaxation at high temperatures is due to local molecular vibrations. These results indicate that, with judicious molecular design, magnetic data storage in single molecules at temperatures above liquid nitrogen should be possible.

Magnetic molecules back in the race

“…In principle, such molecules could be used to store information, but this would require operating temperatures approaching at least that of liquid nitrogen (about 77 K). On page 439 and writing in Angewandte Chemie, respectively, Goodwin et al 2 and Guo et al 3 report a remarkable advance in this direction. The authors demonstrate magnetic bistability in a molecule at temperatures as high as 60 K, which is twice that achieved in previous studies 4 .…”

“…Nevertheless, this study is paving the way as part of investigations that might lead to CRISPR-Cas9 reaching the clinic in the future. 2 and Guo et al 3 report a molecule that has two stable magnetic states -a property called magnetic bistability -at temperatures approaching that required for data-storage applications. To synthesize their molecule, the authors sandwiched a dysprosium ion (Dy 3+ ) between two five-membered carbon rings called cyclopentadienyl anions (Cp − ).…”

“…To synthesize their molecule, the authors sandwiched a dysprosium ion (Dy 3+ ) between two five-membered carbon rings called cyclopentadienyl anions (Cp − ). Each ring had three t-butyl [C(CH 3 ) 3 ] substituents attached, and the authors added a chloride ion (Cl − ) to the Dy 3+ ion to create a neutral [(Cp) 2 DyCl] complex. At this stage, the molecule's magnetic moment (purple arrow) was free to fluctuate between two opposite orientations.…”

“…At this stage, the molecule's magnetic moment (purple arrow) was free to fluctuate between two opposite orientations. The authors then chemically removed the Cl -ion to produce a charged [(Cp) 2 Dy] + complex. They showed that the molecule's magnetic moment was fixed in one of the two possible orientations, depending on the direction of a previously applied magnetic field (not shown).…”

Room Temperature Uniaxial Magnetic Anisotropy Induced By Fe‐Islands in the InSe Semiconductor Van Der Waals Crystal

“…Magnetic anisotropy has been demonstrated in several material systems, ranging from magnetic ion nanoclusters2 and single‐molecule magnets3 to single atoms 4. However, the integration of magnetic and semiconducting properties within the same material system is generally difficult to achieve.…”