Anisotropic Ferromagnetic Organic Nanoflowers
Sajitha Sasidharan, Sayandeep Ghosh, Rishi Sreedhar, Kalpana Kumari, Subhash Thota, Vibin Ramakrishnan
Abstract
We report a weak anisotropic ferromagnetic behavior in a purely organic molecule at room temperature, a property rarely reported in organic nanomaterials. The reported 1,2-bis(tritylthio)ethane, forming plate- and organic-flower-like morphologies at the nanolevel, is the first organic crystal with an inherent magnetic property at 300 and 2 K. However, at low temperatures, the magnetization value [Mmax(T) ∼ 116 emu/mol at 2 K] increases drastically at 3 orders higher compared to 300 K. Interestingly, the system exhibits strong anisotropy with an anisotropic constant, K1 ∼ 3.25 × 103 erg/cc, and anisotropy field, HK ∼ 3.25 kOe. Below 10 K, this system displays unusual temperature dependence of the coercive field [HC(T)] and remanence magnetization [MR(T)] with a hysteresis-peak anomaly (T* ∼ 10–15 K) due to the enhanced spin–orbit coupling. The maximum HC and MR at T* were HC = 220 Oe and MR ∼ 12 emu/mol, respectively. Beyond T*, HC(T) and MR(T) drop continuously and become negligible as the measurement temperature approaches 300 K. Our results demonstrate that the triphenyl molecules can be further exploited for the design and synthesis of organic magnets for possible applications in spintronics and memory storage devices.