We have measured the spin-wave spectrum of the half-doped bilayer manganite Pr(Ca,Sr)(2)Mn(2)O(7) in its spin, charge, and orbital ordered phase. The measurements, which extend throughout the Brillouin zone and cover the entire one-magnon spectrum, are compared critically with spin-wave calculations for different models of the electronic ground state. The data are described very well by the Goodenough model, which has weakly interacting ferromagnetic zig-zag chains in the CE-type arrangement. A model that allows ferromagnetic dimers to form within the zigzags is inconsistent with the data. The analysis conclusively rules out the strongly bound dimer (Zener polaron) model.

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Particles of diamond in the 5–100 nm size range, known as nanodiamond (ND), have shown promise as robust fluorophores for optical imaging. We demonstrate here that, due to their photostability, they are not only suitable for two-photon imaging, but also allow significant resolution enhancement when combined with computational super-resolution techniques. We observe a resolution of 42.5 nm when processing two-photon images with the Super-Resolution Radial Fluctuations algorithm. We show manipulation of the point-spread function of the microscope using adaptive optics. This demonstrates how the photostability of ND can also be of use when characterizing adaptive optics technologies or testing the resilience of super-resolution or aberration correction algorithms.

We present the results of detailed dielectric investigations of the relaxation dynamics in DyMnO3 multiferroic manganite. Strong low-frequency relaxation process near the paraelectricferroelectric phase transition is observed. We provide an experimental evidence that this relaxation mode corresponds to a chirality switching of the spin cycloid in DyMnO3. We demonstrate that the relaxation dynamics in DyMnO3 is typical for an order-disorder phase transition and may be understood within a simple model with a double well potential. These results suggest the interpretation of the paraelectric sinusoidal phase in manganites as a dynamical equilibrium of magnetic cycloids with opposite chiralities.

Particles of diamond in the 5 to 100 nm size range, known as nanodiamond, have shown promise as robust fluorophores for optical imaging. We demonstrate here that, due to their photostability, they are not only suitable for two-photon imaging, but they allow significant resolution enhancement when combined with computational super-resolution techniques. We observe a resolution of 42.5 nm when processing two-photon images with the Super-Resolution Radial Fluctuations algorithm. We show manipulation of the point-spread function of the microscope using adaptive optics. This demonstrates how the photostability of nanodiamond can also be of use when characterising adaptive optics technologies or testing the resilience of super-resolution or aberration correction algorithms. Nanodiamond | Super-resolution | Multi-photon Excitation | Adaptive Optics Correspondence: brian.patton@strath.ac.uk Patton et al. | bioRχiv | March 22, 2019 | 1-7