Observation of a magnetic transition in para-pyridyl nitronyl nitroxide using zero-field μSR

Muon studies of organic ferromagnets and conductors

“…The reduced local field is consistent with a canted magnetic structure [7]. The crystal structure of p-PYNN is very different and consists of onedimensional chains in which molecules are arranged side-by-side and head-totail [8]. This favors ferromagnetic interactions along the chain but the inter-chain interactions are thought to be antiferromagnetic.…”

“…Weak ~tSR oscillations below ~90 mK (Fig. 2c) are observed superimposed on a large background [8], reflecting this more complicated magnetic structure. The temperature dependence of the precession frequencies of these three materials is shown in Fig.…”

“…Small chemical changes to the rest of the molecule lead to significant changes in crystal structure, thereby altering the intermolecular overlaps and thus the magnetic interactions between unpaired spins on neighboring molecules. Thus, different compounds have greatly different magnetic ground states and these can be effectively studied using ~tSR [5][6][7][8][9][10][11][12].…”

“…The time evolution of the muon polarization (A,,(t)) in a polycrystalline mosaic of a p-NPNN[6], la 3-QNNN[9] ande p-PYNN[8] crystals in zero field asa function of temperature.Traces are vertically offset for clarity.The dependence of the magnetic ground state on the molecular shape is well illustrated by the chemical isomers 1-NAPNN and 2-NAPNN (seeFig. 1) whose different molecular shapes leads to different crystal packing and consequently The temperature dependence of the muon spin precession frequencies in p-NPNN, 3-QNNN and p-PYNN.…”

Muon-spin-rotation studies of organic magnets

“…The temperature dependence of the precession frequency (ν µ (T )) of these oscillations is shown in figure 4 together with the calculated local internal field. This is fitted (Blundell et al . 1994(Blundell et al .…”