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MnGe: Itinerant magnet with strong spin-orbit effects John F. DiTusa, Louisiana State University & Agricultural and mechanical College , DMR 0804376.
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MnGe: Itinerant magnet with strong spin-orbit effectsJohn F. DiTusa, Louisiana State University & Agricultural and mechanical College, DMR 0804376 We have explored the magnetism and electrical transport properties of MnGe which forms in the cubic B20 crystal structure under high pressure conditions. MnGe is one of several monosilicide and monogermanide phases to form in this structure that lacks inversion symmetry. The low crystal symmetry and the spin-orbit interaction cause the itinerant magnetic phases that form to have long range twists (l<70 nm) of their magnetizations, helimagnetism. These phases are interesting, in part, because under certain conditions of temperature, magnetic field, and sample size the magnetic state transitions into one of a crystal of topologically stable knots of spin structure, or Skyrmions. Here we present the magnetization (top frame), and the Hall effect (lower frame) of MnGe where a magnetic state with unusual temperature and magnetic field dependencies is apparent below 220 K. The magnetization displays several transitions that are also apparent in the anomalous Hall effect.
Graduate and Undergraduate Education, Research and OutreachJohn F. DiTusa, Louisiana State University & Agricultural and mechanical College, DMR 0804376 REU students Noah Davis (left) of LSU and Dylan Liu (right) of Columbia University at the LSU SURF poster session. Mr. Davis and Mr. Liu each grew polycrystalline and crystalline semiconducting and magnetic materials for investigations in my laboratory. Over 20 undergraduate students have participated in the NSF supported research, many have gone on to graduate programs and careers in science.This grant also supported the work of Teach for America participant Joshua Miller, a science and Math teacher at Capital Heights High school. This program sought to engage minority high school students through his work and visits of his students to our labs Education: The work ofPhysics graduate Students Drew Rebar and Yan Wu, and undergraduate students Eric O’Quinn, Laura Clessi, Josua Mendez, Dominique Gautreau, and Kisa Valenti is supported by this research grant. Previous post docs and graduate students, whose PhD and masters thesis research were supported by this program, are now employed in research, education, and industry on three continents.