Past experiments done at the Paul Scherrer Institut, probed the thermal switching properties of nano-sized metallic magnetic particles and found a uniaxial super-paramagnetism fluctuating at the seconds timescale. Until now, this result has lacked a quantitative understanding.
Magnetic Cobalt particles are known to contain planar defects such as twins and stacking faults and recent theoretical developments [PRB 110, 134419 (2024)] gives the theoretical framework to determine their effect on the thermal magnetic properties. What comes out of these calculations is a prefactor that depends exponentially on defect content, giving numerical values that differ by orders-of-magnitude through the addition of just a few twin or stacking fault defects and a quantitative understanding of the experimentally observed super-paramagnetism.