Magnetic Bistability in an Organic Radical-Based Charge Transfer Cocrystal

Area of Science:

• Materials Science
• Organic Chemistry
• Solid-State Physics

Background:

• Organic bistable materials are crucial for advanced electronic applications.
• Developing new materials with switchable magnetic properties is an active research area.
• Charge transfer cocrystals offer unique pathways to engineer material properties.

Purpose of the Study:

• To synthesize and characterize a novel organic charge transfer cocrystal.
• To investigate the magnetic bistability and thermal properties of the cocrystal.
• To elucidate the molecular mechanisms underlying the observed magnetic behavior.

Main Methods:

• Synthesis of an organic charge transfer cocrystal complex.
• X-ray crystallographic studies to determine crystal structure.
• Theoretical calculations to understand electronic structure and interactions.
• Magnetic property measurements over a range of temperatures.

Main Results:

• An all-organic-based magnetic bistable material was successfully created.
• The material exhibits a thermally activated magnetic hysteresis loop from 170 to 260 K.
• Formation of a π-associated radical anion dimer and temperature-dependent π-stacking distances were observed.
• Distinct singlet states with varying singlet-triplet gaps were identified.

Conclusions:

• The charge transfer cocrystal of TPVr and TCNQF demonstrates thermally excited molecular magnetic bistability.
• The observed bistability arises from temperature-dependent changes in π-stacking and electronic states within TCNQF dimers.
• This work presents a rare example of organic-based magnetic bistable materials with potential for future applications.