@article{lippy_bland_bataller_2021, title={Fundamental interactions in a classical Wigner system}, volume={104}, ISSN={["2470-0053"]}, DOI={10.1103/PhysRevE.104.L023202}, abstractNote={Wigner crystallization in macroscopic systems provides a simple avenue for studying classical many-body physics. The Coulomb repulsion of millimeter-sized conducting spheres rolling on a high potential surface enables the self-assembly of ordered structures. Prior attempts at formulating pairwise force models for Wigner islands have resulted in different functional forms with no apparent consensus. In this study, we explore fundamental particle interactions using the finite element method to solve the electrostatic problem for one-, two-, and many-sphere configurations. Analysis of charge and force shows three interaction regimes parametrized by the packing fraction, which includes many-body force behavior for compact geometries. We find that the force relationship between spheres is accurately represented by an aligned dipole model over all configurations. Both the finite element method and aligned dipole models were validated in absolute terms using an experimental setup featuring a gravity potential. Future dynamic studies, which rely on accurate force relationships, can now be treated.}, number={2}, journal={PHYSICAL REVIEW E}, author={Lippy, Matthew and Bland, Hayden and Bataller, Alexander}, year={2021}, month={Aug} }
 @article{koohfar_ozbek_bland_zhang_kumah_2021, title={Interface-driven magnetic anisotropy in relaxed La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 heterostructures on MgO}, volume={129}, ISSN={["1089-7550"]}, url={https://doi.org/10.1063/5.0033236}, DOI={10.1063/5.0033236}, abstractNote={We investigate the structural and magnetic properties of La0.7Sr0.3CrO3 (LSCO)/La0.7Sr0.3MnO3 (LSMO) heterostructures grown on (001)-oriented MgO by molecular beam epitaxy. Due to the large film-substrate lattice mismatch, strain relaxation is found to occur within the first 2–3 unit cells (uc) of the film as evidenced by reflection high energy electron diffraction and high-resolution synchrotron x-ray reciprocal space mapping. We find that the presence of the LSCO spacer and capping layers leads to ferromagnetism in ultra-thin LSMO layers with thicknesses of the order of 2 uc with the magnetic easy axis oriented in the film plane. Net magnetic moments of 1.4 and 2.4 μB/Mn are measured for (2 uc LSCO/2 uc LSMO) and (2 uc LSCO/4 uc LSMO) superlattices, respectively, by superconducting quantum interference device magnetometry. The effective magnetic anisotropy of the relaxed (2 uc LSCO/4 uc LSMO) heterostructure is found to be an order of magnitude higher than bulk LSMO highlighting the critical role of interfacial interactions in tuning magnetic anisotropy at complex oxide interfaces.}, number={5}, journal={JOURNAL OF APPLIED PHYSICS}, author={Koohfar, Sanaz and Ozbek, Yasemin and Bland, Hayden and Zhang, Zhan and Kumah, Divine P.}, year={2021}, month={Feb} }